Make workspace context reflect real git state

Git-aware CLI flows already existed, but branch detection depended on
status-line parsing and /diff hid local policy inside a path exclusion.
This change makes branch resolution and diff rendering rely on git-native
queries, adds staged+unstaged diff reporting, and threads git diff
snapshots into runtime project context so prompts see the same workspace
state users inspect from the CLI.

Constraint: No new dependencies for git integration work
Constraint: Slash-command help/behavior must stay aligned between shared metadata and CLI handlers
Rejected: Keep parsing the `## ...` status line only | brittle for detached HEAD and format drift
Rejected: Keep hard-coded `:(exclude).omx` filtering | redundant with git ignore rules and hides product policy in implementation
Confidence: high
Scope-risk: moderate
Reversibility: clean
Directive: Preserve git-native behavior for branch/diff reporting; do not reintroduce ad hoc ignore filtering without a product requirement
Tested: cargo fmt; cargo clippy --workspace --all-targets -- -D warnings; cargo test --workspace
Not-tested: Manual REPL /diff smoke test against a live interactive session

rust/crates/api/src/lib.rs

@@ -11,7 +11,7 @@ pub use error::ApiError;
 pub use sse::{parse_frame, SseParser};
 pub use types::{
     ContentBlockDelta, ContentBlockDeltaEvent, ContentBlockStartEvent, ContentBlockStopEvent,
-    ImageSource, InputContentBlock, InputMessage, MessageDelta, MessageDeltaEvent, MessageRequest,
+    InputContentBlock, InputMessage, MessageDelta, MessageDeltaEvent, MessageRequest,
     MessageResponse, MessageStartEvent, MessageStopEvent, OutputContentBlock, StreamEvent,
     ToolChoice, ToolDefinition, ToolResultContentBlock, Usage,
 };

rust/crates/api/src/types.rs

@@ -64,9 +64,6 @@ pub enum InputContentBlock {
     Text {
         text: String,
     },
-    Image {
-        source: ImageSource,
-    },
     ToolUse {
         id: String,
         name: String,
@@ -80,14 +77,6 @@ pub enum InputContentBlock {
     },
 }
 
-#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
-pub struct ImageSource {
-    #[serde(rename = "type")]
-    pub kind: String,
-    pub media_type: String,
-    pub data: String,
-}
-
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[serde(tag = "type", rename_all = "snake_case")]
 pub enum ToolResultContentBlock {

rust/crates/api/tests/client_integration.rs

@@ -4,8 +4,8 @@ use std::time::Duration;
 
 use api::{
     AnthropicClient, ApiError, ContentBlockDelta, ContentBlockDeltaEvent, ContentBlockStartEvent,
-    ImageSource, InputContentBlock, InputMessage, MessageDeltaEvent, MessageRequest,
-    OutputContentBlock, StreamEvent, ToolChoice, ToolDefinition,
+    InputContentBlock, InputMessage, MessageDeltaEvent, MessageRequest, OutputContentBlock,
+    StreamEvent, ToolChoice, ToolDefinition,
 };
 use serde_json::json;
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
@@ -75,39 +75,6 @@ async fn send_message_posts_json_and_parses_response() {
     assert_eq!(body["tool_choice"]["type"], json!("auto"));
 }
 
-#[test]
-fn image_content_blocks_serialize_with_base64_source() {
-    let request = MessageRequest {
-        model: "claude-3-7-sonnet-latest".to_string(),
-        max_tokens: 64,
-        messages: vec![InputMessage {
-            role: "user".to_string(),
-            content: vec![InputContentBlock::Image {
-                source: ImageSource {
-                    kind: "base64".to_string(),
-                    media_type: "image/png".to_string(),
-                    data: "AQID".to_string(),
-                },
-            }],
-        }],
-        system: None,
-        tools: None,
-        tool_choice: None,
-        stream: false,
-    };
-
-    let json = serde_json::to_value(request).expect("request should serialize");
-    assert_eq!(json["messages"][0]["content"][0]["type"], json!("image"));
-    assert_eq!(
-        json["messages"][0]["content"][0]["source"],
-        json!({
-            "type": "base64",
-            "media_type": "image/png",
-            "data": "AQID"
-        })
-    );
-}
-
 #[tokio::test]
 async fn stream_message_parses_sse_events_with_tool_use() {
     let state = Arc::new(Mutex::new(Vec::<CapturedRequest>::new()));

rust/crates/runtime/src/conversation.rs

@@ -414,6 +414,7 @@ mod tests {
                 cwd: PathBuf::from("/tmp/project"),
                 current_date: "2026-03-31".to_string(),
                 git_status: None,
+                git_diff: None,
                 instruction_files: Vec::new(),
             })
             .with_os("linux", "6.8")

rust/crates/runtime/src/prompt.rs

@@ -50,6 +50,7 @@ pub struct ProjectContext {
     pub cwd: PathBuf,
     pub current_date: String,
     pub git_status: Option<String>,
+    pub git_diff: Option<String>,
     pub instruction_files: Vec<ContextFile>,
 }
 
@@ -64,6 +65,7 @@ impl ProjectContext {
             cwd,
             current_date: current_date.into(),
             git_status: None,
+            git_diff: None,
             instruction_files,
         })
     }
@@ -74,6 +76,7 @@ impl ProjectContext {
     ) -> std::io::Result<Self> {
         let mut context = Self::discover(cwd, current_date)?;
         context.git_status = read_git_status(&context.cwd);
+        context.git_diff = read_git_diff(&context.cwd);
         Ok(context)
     }
 }
@@ -239,6 +242,38 @@ fn read_git_status(cwd: &Path) -> Option<String> {
     }
 }
 
+fn read_git_diff(cwd: &Path) -> Option<String> {
+    let mut sections = Vec::new();
+
+    let staged = read_git_output(cwd, &["diff", "--cached"])?;
+    if !staged.trim().is_empty() {
+        sections.push(format!("Staged changes:\n{}", staged.trim_end()));
+    }
+
+    let unstaged = read_git_output(cwd, &["diff"])?;
+    if !unstaged.trim().is_empty() {
+        sections.push(format!("Unstaged changes:\n{}", unstaged.trim_end()));
+    }
+
+    if sections.is_empty() {
+        None
+    } else {
+        Some(sections.join("\n\n"))
+    }
+}
+
+fn read_git_output(cwd: &Path, args: &[&str]) -> Option<String> {
+    let output = Command::new("git")
+        .args(args)
+        .current_dir(cwd)
+        .output()
+        .ok()?;
+    if !output.status.success() {
+        return None;
+    }
+    String::from_utf8(output.stdout).ok()
+}
+
 fn render_project_context(project_context: &ProjectContext) -> String {
     let mut lines = vec!["# Project context".to_string()];
     let mut bullets = vec![
@@ -257,6 +292,11 @@ fn render_project_context(project_context: &ProjectContext) -> String {
         lines.push("Git status snapshot:".to_string());
         lines.push(status.clone());
     }
+    if let Some(diff) = &project_context.git_diff {
+        lines.push(String::new());
+        lines.push("Git diff snapshot:".to_string());
+        lines.push(diff.clone());
+    }
     lines.join("\n")
 }
 
@@ -577,6 +617,49 @@ mod tests {
         assert!(status.contains("## No commits yet on") || status.contains("## "));
         assert!(status.contains("?? CLAUDE.md"));
         assert!(status.contains("?? tracked.txt"));
+        assert!(context.git_diff.is_none());
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
+
+    #[test]
+    fn discover_with_git_includes_diff_snapshot_for_tracked_changes() {
+        let root = temp_dir();
+        fs::create_dir_all(&root).expect("root dir");
+        std::process::Command::new("git")
+            .args(["init", "--quiet"])
+            .current_dir(&root)
+            .status()
+            .expect("git init should run");
+        std::process::Command::new("git")
+            .args(["config", "user.email", "tests@example.com"])
+            .current_dir(&root)
+            .status()
+            .expect("git config email should run");
+        std::process::Command::new("git")
+            .args(["config", "user.name", "Runtime Prompt Tests"])
+            .current_dir(&root)
+            .status()
+            .expect("git config name should run");
+        fs::write(root.join("tracked.txt"), "hello\n").expect("write tracked file");
+        std::process::Command::new("git")
+            .args(["add", "tracked.txt"])
+            .current_dir(&root)
+            .status()
+            .expect("git add should run");
+        std::process::Command::new("git")
+            .args(["commit", "-m", "init", "--quiet"])
+            .current_dir(&root)
+            .status()
+            .expect("git commit should run");
+        fs::write(root.join("tracked.txt"), "hello\nworld\n").expect("rewrite tracked file");
+
+        let context =
+            ProjectContext::discover_with_git(&root, "2026-03-31").expect("context should load");
+
+        let diff = context.git_diff.expect("git diff should be present");
+        assert!(diff.contains("Unstaged changes:"));
+        assert!(diff.contains("tracked.txt"));
 
         fs::remove_dir_all(root).expect("cleanup temp dir");
     }

rust/crates/rusty-claude-cli/src/main.rs

@@ -11,8 +11,8 @@ use std::process::Command;
 use std::time::{SystemTime, UNIX_EPOCH};
 
 use api::{
-    resolve_startup_auth_source, AnthropicClient, AuthSource, ContentBlockDelta, ImageSource,
-    InputContentBlock, InputMessage, MessageRequest, MessageResponse, OutputContentBlock,
+    resolve_startup_auth_source, AnthropicClient, AuthSource, ContentBlockDelta, InputContentBlock,
+    InputMessage, MessageRequest, MessageResponse, OutputContentBlock,
     StreamEvent as ApiStreamEvent, ToolChoice, ToolDefinition, ToolResultContentBlock,
 };
 
@@ -41,7 +41,6 @@ const BUILD_TARGET: Option<&str> = option_env!("TARGET");
 const GIT_SHA: Option<&str> = option_env!("GIT_SHA");
 
 type AllowedToolSet = BTreeSet<String>;
-const IMAGE_REF_PREFIX: &str = "@";
 
 fn main() {
     if let Err(error) = run() {
@@ -743,27 +742,61 @@ fn format_compact_report(removed: usize, resulting_messages: usize, skipped: boo
 }
 
 fn parse_git_status_metadata(status: Option<&str>) -> (Option<PathBuf>, Option<String>) {
-    let Some(status) = status else {
-        return (None, None);
-    };
-    let branch = status.lines().next().and_then(|line| {
-        line.strip_prefix("## ")
-            .map(|line| {
-                line.split(['.', ' '])
-                    .next()
-                    .unwrap_or_default()
-                    .to_string()
-            })
-            .filter(|value| !value.is_empty())
-    });
-    let project_root = find_git_root().ok();
-    (project_root, branch)
+    parse_git_status_metadata_for(
+        &env::current_dir().unwrap_or_else(|_| PathBuf::from(".")),
+        status,
+    )
 }
 
-fn find_git_root() -> Result<PathBuf, Box<dyn std::error::Error>> {
+fn parse_git_status_branch(status: Option<&str>) -> Option<String> {
+    let status = status?;
+    let first_line = status.lines().next()?;
+    let line = first_line.strip_prefix("## ")?;
+    if line.starts_with("HEAD") {
+        return Some("detached HEAD".to_string());
+    }
+    let branch = line.split(['.', ' ']).next().unwrap_or_default().trim();
+    if branch.is_empty() {
+        None
+    } else {
+        Some(branch.to_string())
+    }
+}
+
+fn resolve_git_branch_for(cwd: &Path) -> Option<String> {
+    let branch = run_git_capture_in(cwd, &["branch", "--show-current"])?;
+    let branch = branch.trim();
+    if !branch.is_empty() {
+        return Some(branch.to_string());
+    }
+
+    let fallback = run_git_capture_in(cwd, &["rev-parse", "--abbrev-ref", "HEAD"])?;
+    let fallback = fallback.trim();
+    if fallback.is_empty() {
+        None
+    } else if fallback == "HEAD" {
+        Some("detached HEAD".to_string())
+    } else {
+        Some(fallback.to_string())
+    }
+}
+
+fn run_git_capture_in(cwd: &Path, args: &[&str]) -> Option<String> {
+    let output = std::process::Command::new("git")
+        .args(args)
+        .current_dir(cwd)
+        .output()
+        .ok()?;
+    if !output.status.success() {
+        return None;
+    }
+    String::from_utf8(output.stdout).ok()
+}
+
+fn find_git_root_in(cwd: &Path) -> Result<PathBuf, Box<dyn std::error::Error>> {
     let output = std::process::Command::new("git")
         .args(["rev-parse", "--show-toplevel"])
-        .current_dir(env::current_dir()?)
+        .current_dir(cwd)
         .output()?;
     if !output.status.success() {
         return Err("not a git repository".into());
@@ -775,6 +808,15 @@ fn find_git_root() -> Result<PathBuf, Box<dyn std::error::Error>> {
     Ok(PathBuf::from(path))
 }
 
+fn parse_git_status_metadata_for(
+    cwd: &Path,
+    status: Option<&str>,
+) -> (Option<PathBuf>, Option<String>) {
+    let branch = resolve_git_branch_for(cwd).or_else(|| parse_git_status_branch(status));
+    let project_root = find_git_root_in(cwd).ok();
+    (project_root, branch)
+}
+
 #[allow(clippy::too_many_lines)]
 fn run_resume_command(
     session_path: &Path,
@@ -862,7 +904,9 @@ fn run_resume_command(
         }),
         SlashCommand::Diff => Ok(ResumeCommandOutcome {
             session: session.clone(),
-            message: Some(render_diff_report()?),
+            message: Some(render_diff_report_for(
+                session_path.parent().unwrap_or_else(|| Path::new(".")),
+            )?),
         }),
         SlashCommand::Version => Ok(ResumeCommandOutcome {
             session: session.clone(),
@@ -1043,7 +1087,9 @@ impl LiveCli {
             max_tokens: DEFAULT_MAX_TOKENS,
             messages: vec![InputMessage {
                 role: "user".to_string(),
-                content: prompt_to_content_blocks(input, &env::current_dir()?)?,
+                content: vec![InputContentBlock::Text {
+                    text: input.to_string(),
+                }],
             }],
             system: (!self.system_prompt.is_empty()).then(|| self.system_prompt.join("\n\n")),
             tools: None,
@@ -1794,22 +1840,43 @@ fn normalize_permission_mode(mode: &str) -> Option<&'static str> {
 }
 
 fn render_diff_report() -> Result<String, Box<dyn std::error::Error>> {
-    let output = std::process::Command::new("git")
-        .args(["diff", "--", ":(exclude).omx"])
-        .current_dir(env::current_dir()?)
-        .output()?;
-    if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
-        return Err(format!("git diff failed: {stderr}").into());
-    }
-    let diff = String::from_utf8(output.stdout)?;
-    if diff.trim().is_empty() {
+    render_diff_report_for(&env::current_dir()?)
+}
+
+fn render_diff_report_for(cwd: &Path) -> Result<String, Box<dyn std::error::Error>> {
+    let staged = run_git_diff_command_in(cwd, &["diff", "--cached"])?;
+    let unstaged = run_git_diff_command_in(cwd, &["diff"])?;
+    if staged.trim().is_empty() && unstaged.trim().is_empty() {
         return Ok(
             "Diff\n  Result           clean working tree\n  Detail           no current changes"
                 .to_string(),
         );
     }
-    Ok(format!("Diff\n\n{}", diff.trim_end()))
+
+    let mut sections = Vec::new();
+    if !staged.trim().is_empty() {
+        sections.push(format!("Staged changes:\n{}", staged.trim_end()));
+    }
+    if !unstaged.trim().is_empty() {
+        sections.push(format!("Unstaged changes:\n{}", unstaged.trim_end()));
+    }
+
+    Ok(format!("Diff\n\n{}", sections.join("\n\n")))
+}
+
+fn run_git_diff_command_in(
+    cwd: &Path,
+    args: &[&str],
+) -> Result<String, Box<dyn std::error::Error>> {
+    let output = std::process::Command::new("git")
+        .args(args)
+        .current_dir(cwd)
+        .output()?;
+    if !output.status.success() {
+        let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
+        return Err(format!("git {} failed: {stderr}", args.join(" ")).into());
+    }
+    Ok(String::from_utf8(output.stdout)?)
 }
 
 fn render_version_report() -> String {
@@ -2020,7 +2087,7 @@ impl ApiClient for AnthropicRuntimeClient {
         let message_request = MessageRequest {
             model: self.model.clone(),
             max_tokens: DEFAULT_MAX_TOKENS,
-            messages: convert_messages(&request.messages)?,
+            messages: convert_messages(&request.messages),
             system: (!request.system_prompt.is_empty()).then(|| request.system_prompt.join("\n\n")),
             tools: self.enable_tools.then(|| {
                 filter_tool_specs(self.allowed_tools.as_ref())
@@ -2299,10 +2366,7 @@ fn tool_permission_specs() -> Vec<ToolSpec> {
     mvp_tool_specs()
 }
 
-fn convert_messages(messages: &[ConversationMessage]) -> Result<Vec<InputMessage>, RuntimeError> {
-    let cwd = env::current_dir().map_err(|error| {
-        RuntimeError::new(format!("failed to resolve current directory: {error}"))
-    })?;
+fn convert_messages(messages: &[ConversationMessage]) -> Vec<InputMessage> {
     messages
         .iter()
         .filter_map(|message| {
@@ -2313,224 +2377,36 @@ fn convert_messages(messages: &[ConversationMessage]) -> Result<Vec<InputMessage
             let content = message
                 .blocks
                 .iter()
-                .try_fold(Vec::new(), |mut acc, block| {
-                    match block {
-                        ContentBlock::Text { text } => {
-                            if message.role == MessageRole::User {
-                                acc.extend(
-                                    prompt_to_content_blocks(text, &cwd)
-                                        .map_err(RuntimeError::new)?,
-                                );
-                            } else {
-                                acc.push(InputContentBlock::Text { text: text.clone() });
-                            }
-                        }
-                        ContentBlock::ToolUse { id, name, input } => {
-                            acc.push(InputContentBlock::ToolUse {
-                                id: id.clone(),
-                                name: name.clone(),
-                                input: serde_json::from_str(input)
-                                    .unwrap_or_else(|_| serde_json::json!({ "raw": input })),
-                            });
-                        }
-                        ContentBlock::ToolResult {
-                            tool_use_id,
-                            output,
-                            is_error,
-                            ..
-                        } => acc.push(InputContentBlock::ToolResult {
-                            tool_use_id: tool_use_id.clone(),
-                            content: vec![ToolResultContentBlock::Text {
-                                text: output.clone(),
-                            }],
-                            is_error: *is_error,
-                        }),
-                    }
-                    Ok::<_, RuntimeError>(acc)
-                });
-            match content {
-                Ok(content) if !content.is_empty() => Some(Ok(InputMessage {
-                    role: role.to_string(),
-                    content,
-                })),
-                Ok(_) => None,
-                Err(error) => Some(Err(error)),
-            }
+                .map(|block| match block {
+                    ContentBlock::Text { text } => InputContentBlock::Text { text: text.clone() },
+                    ContentBlock::ToolUse { id, name, input } => InputContentBlock::ToolUse {
+                        id: id.clone(),
+                        name: name.clone(),
+                        input: serde_json::from_str(input)
+                            .unwrap_or_else(|_| serde_json::json!({ "raw": input })),
+                    },
+                    ContentBlock::ToolResult {
+                        tool_use_id,
+                        output,
+                        is_error,
+                        ..
+                    } => InputContentBlock::ToolResult {
+                        tool_use_id: tool_use_id.clone(),
+                        content: vec![ToolResultContentBlock::Text {
+                            text: output.clone(),
+                        }],
+                        is_error: *is_error,
+                    },
+                })
+                .collect::<Vec<_>>();
+            (!content.is_empty()).then(|| InputMessage {
+                role: role.to_string(),
+                content,
+            })
         })
         .collect()
 }
 
-fn prompt_to_content_blocks(input: &str, cwd: &Path) -> Result<Vec<InputContentBlock>, String> {
-    let mut blocks = Vec::new();
-    let mut text_buffer = String::new();
-    let mut chars = input.char_indices().peekable();
-
-    while let Some((index, ch)) = chars.next() {
-        if ch == '!' && input[index..].starts_with("![") {
-            if let Some((alt_end, path_start, path_end)) = parse_markdown_image_ref(input, index) {
-                let _ = alt_end;
-                flush_text_block(&mut blocks, &mut text_buffer);
-                let path = &input[path_start..path_end];
-                blocks.push(load_image_block(path, cwd)?);
-                while let Some((next_index, _)) = chars.peek() {
-                    if *next_index < path_end + 1 {
-                        let _ = chars.next();
-                    } else {
-                        break;
-                    }
-                }
-                continue;
-            }
-        }
-
-        if ch == '@' && is_ref_boundary(input[..index].chars().next_back()) {
-            let path_end = find_path_end(input, index + 1);
-            if path_end > index + 1 {
-                let candidate = &input[index + 1..path_end];
-                if looks_like_image_ref(candidate, cwd) {
-                    flush_text_block(&mut blocks, &mut text_buffer);
-                    blocks.push(load_image_block(candidate, cwd)?);
-                    while let Some((next_index, _)) = chars.peek() {
-                        if *next_index < path_end {
-                            let _ = chars.next();
-                        } else {
-                            break;
-                        }
-                    }
-                    continue;
-                }
-            }
-        }
-
-        text_buffer.push(ch);
-    }
-
-    flush_text_block(&mut blocks, &mut text_buffer);
-    if blocks.is_empty() {
-        blocks.push(InputContentBlock::Text {
-            text: input.to_string(),
-        });
-    }
-    Ok(blocks)
-}
-
-fn parse_markdown_image_ref(input: &str, start: usize) -> Option<(usize, usize, usize)> {
-    let after_bang = input.get(start + 2..)?;
-    let alt_end_offset = after_bang.find("](")?;
-    let path_start = start + 2 + alt_end_offset + 2;
-    let remainder = input.get(path_start..)?;
-    let path_end_offset = remainder.find(')')?;
-    let path_end = path_start + path_end_offset;
-    Some((start + 2 + alt_end_offset, path_start, path_end))
-}
-
-fn is_ref_boundary(ch: Option<char>) -> bool {
-    ch.is_none_or(char::is_whitespace)
-}
-
-fn find_path_end(input: &str, start: usize) -> usize {
-    input[start..]
-        .char_indices()
-        .find_map(|(offset, ch)| (ch.is_whitespace()).then_some(start + offset))
-        .unwrap_or(input.len())
-}
-
-fn looks_like_image_ref(candidate: &str, cwd: &Path) -> bool {
-    let resolved = resolve_prompt_path(candidate, cwd);
-    media_type_for_path(Path::new(candidate)).is_some()
-        || resolved.is_file()
-        || candidate.contains(std::path::MAIN_SEPARATOR)
-        || candidate.starts_with("./")
-        || candidate.starts_with("../")
-}
-
-fn flush_text_block(blocks: &mut Vec<InputContentBlock>, text_buffer: &mut String) {
-    if text_buffer.is_empty() {
-        return;
-    }
-    blocks.push(InputContentBlock::Text {
-        text: std::mem::take(text_buffer),
-    });
-}
-
-fn load_image_block(path_ref: &str, cwd: &Path) -> Result<InputContentBlock, String> {
-    let resolved = resolve_prompt_path(path_ref, cwd);
-    let media_type = media_type_for_path(&resolved).ok_or_else(|| {
-        format!(
-            "unsupported image format for reference {IMAGE_REF_PREFIX}{path_ref}; supported: png, jpg, jpeg, gif, webp"
-        )
-    })?;
-    let bytes = fs::read(&resolved).map_err(|error| {
-        format!(
-            "failed to read image reference {}: {error}",
-            resolved.display()
-        )
-    })?;
-    Ok(InputContentBlock::Image {
-        source: ImageSource {
-            kind: "base64".to_string(),
-            media_type: media_type.to_string(),
-            data: encode_base64(&bytes),
-        },
-    })
-}
-
-fn resolve_prompt_path(path_ref: &str, cwd: &Path) -> PathBuf {
-    let path = Path::new(path_ref);
-    if path.is_absolute() {
-        path.to_path_buf()
-    } else {
-        cwd.join(path)
-    }
-}
-
-fn media_type_for_path(path: &Path) -> Option<&'static str> {
-    let extension = path.extension()?.to_str()?.to_ascii_lowercase();
-    match extension.as_str() {
-        "png" => Some("image/png"),
-        "jpg" | "jpeg" => Some("image/jpeg"),
-        "gif" => Some("image/gif"),
-        "webp" => Some("image/webp"),
-        _ => None,
-    }
-}
-
-fn encode_base64(bytes: &[u8]) -> String {
-    const TABLE: &[u8; 64] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
-    let mut output = String::new();
-    let mut index = 0;
-    while index + 3 <= bytes.len() {
-        let block = (u32::from(bytes[index]) << 16)
-            | (u32::from(bytes[index + 1]) << 8)
-            | u32::from(bytes[index + 2]);
-        output.push(TABLE[((block >> 18) & 0x3F) as usize] as char);
-        output.push(TABLE[((block >> 12) & 0x3F) as usize] as char);
-        output.push(TABLE[((block >> 6) & 0x3F) as usize] as char);
-        output.push(TABLE[(block & 0x3F) as usize] as char);
-        index += 3;
-    }
-
-    match bytes.len().saturating_sub(index) {
-        1 => {
-            let block = u32::from(bytes[index]) << 16;
-            output.push(TABLE[((block >> 18) & 0x3F) as usize] as char);
-            output.push(TABLE[((block >> 12) & 0x3F) as usize] as char);
-            output.push('=');
-            output.push('=');
-        }
-        2 => {
-            let block = (u32::from(bytes[index]) << 16) | (u32::from(bytes[index + 1]) << 8);
-            output.push(TABLE[((block >> 18) & 0x3F) as usize] as char);
-            output.push(TABLE[((block >> 12) & 0x3F) as usize] as char);
-            output.push(TABLE[((block >> 6) & 0x3F) as usize] as char);
-            output.push('=');
-        }
-        _ => {}
-    }
-
-    output
-}
-
 fn print_help() {
     println!("rusty-claude-cli v{VERSION}");
     println!();
@@ -2583,15 +2459,54 @@ mod tests {
         format_model_report, format_model_switch_report, format_permissions_report,
         format_permissions_switch_report, format_resume_report, format_status_report,
         format_tool_call_start, format_tool_result, normalize_permission_mode, parse_args,
-        parse_git_status_metadata, render_config_report, render_init_claude_md,
-        render_memory_report, render_repl_help, resume_supported_slash_commands, status_context,
-        CliAction, CliOutputFormat, SlashCommand, StatusUsage, DEFAULT_MODEL,
+        parse_git_status_branch, parse_git_status_metadata, render_config_report,
+        render_diff_report, render_init_claude_md, render_memory_report, render_repl_help,
+        resume_supported_slash_commands, run_resume_command, status_context, CliAction,
+        CliOutputFormat, SlashCommand, StatusUsage, DEFAULT_MODEL,
     };
-    use api::InputContentBlock;
-    use runtime::{ContentBlock, ConversationMessage, MessageRole, PermissionMode};
+    use runtime::{ContentBlock, ConversationMessage, MessageRole, PermissionMode, Session};
+    use std::fs;
     use std::path::{Path, PathBuf};
+    use std::process::Command;
+    use std::sync::{Mutex, MutexGuard, OnceLock};
     use std::time::{SystemTime, UNIX_EPOCH};
 
+    fn temp_dir() -> PathBuf {
+        let nanos = SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .expect("time should be after epoch")
+            .as_nanos();
+        std::env::temp_dir().join(format!("rusty-claude-cli-{nanos}"))
+    }
+
+    fn git(args: &[&str], cwd: &Path) {
+        let status = Command::new("git")
+            .args(args)
+            .current_dir(cwd)
+            .status()
+            .expect("git command should run");
+        assert!(
+            status.success(),
+            "git command failed: git {}",
+            args.join(" ")
+        );
+    }
+
+    fn env_lock() -> MutexGuard<'static, ()> {
+        static LOCK: OnceLock<Mutex<()>> = OnceLock::new();
+        LOCK.get_or_init(|| Mutex::new(()))
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+    }
+
+    fn with_current_dir<T>(cwd: &Path, f: impl FnOnce() -> T) -> T {
+        let previous = std::env::current_dir().expect("cwd should load");
+        std::env::set_current_dir(cwd).expect("cwd should change");
+        let result = f();
+        std::env::set_current_dir(previous).expect("cwd should restore");
+        result
+    }
+
     #[test]
     fn defaults_to_repl_when_no_args() {
         assert_eq!(
@@ -2977,19 +2892,140 @@ mod tests {
 
     #[test]
     fn parses_git_status_metadata() {
-        let (root, branch) = parse_git_status_metadata(Some(
-            "## rcc/cli...origin/rcc/cli
+        let _guard = env_lock();
+        let temp_root = temp_dir();
+        fs::create_dir_all(&temp_root).expect("root dir");
+        let (project_root, branch) = with_current_dir(&temp_root, || {
+            parse_git_status_metadata(Some(
+                "## rcc/cli...origin/rcc/cli
  M src/main.rs",
-        ));
+            ))
+        });
         assert_eq!(branch.as_deref(), Some("rcc/cli"));
-        let _ = root;
+        assert!(project_root.is_none());
+        fs::remove_dir_all(temp_root).expect("cleanup temp dir");
+    }
+
+    #[test]
+    fn parses_detached_head_from_status_snapshot() {
+        let _guard = env_lock();
+        assert_eq!(
+            parse_git_status_branch(Some(
+                "## HEAD (no branch)
+ M src/main.rs"
+            )),
+            Some("detached HEAD".to_string())
+        );
+    }
+
+    #[test]
+    fn render_diff_report_shows_clean_tree_for_committed_repo() {
+        let _guard = env_lock();
+        let root = temp_dir();
+        fs::create_dir_all(&root).expect("root dir");
+        git(&["init", "--quiet"], &root);
+        git(&["config", "user.email", "tests@example.com"], &root);
+        git(&["config", "user.name", "Rusty Claude Tests"], &root);
+        fs::write(root.join("tracked.txt"), "hello\n").expect("write file");
+        git(&["add", "tracked.txt"], &root);
+        git(&["commit", "-m", "init", "--quiet"], &root);
+
+        let report = with_current_dir(&root, || {
+            render_diff_report().expect("diff report should render")
+        });
+        assert!(report.contains("clean working tree"));
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
+
+    #[test]
+    fn render_diff_report_includes_staged_and_unstaged_sections() {
+        let _guard = env_lock();
+        let root = temp_dir();
+        fs::create_dir_all(&root).expect("root dir");
+        git(&["init", "--quiet"], &root);
+        git(&["config", "user.email", "tests@example.com"], &root);
+        git(&["config", "user.name", "Rusty Claude Tests"], &root);
+        fs::write(root.join("tracked.txt"), "hello\n").expect("write file");
+        git(&["add", "tracked.txt"], &root);
+        git(&["commit", "-m", "init", "--quiet"], &root);
+
+        fs::write(root.join("tracked.txt"), "hello\nstaged\n").expect("update file");
+        git(&["add", "tracked.txt"], &root);
+        fs::write(root.join("tracked.txt"), "hello\nstaged\nunstaged\n")
+            .expect("update file twice");
+
+        let report = with_current_dir(&root, || {
+            render_diff_report().expect("diff report should render")
+        });
+        assert!(report.contains("Staged changes:"));
+        assert!(report.contains("Unstaged changes:"));
+        assert!(report.contains("tracked.txt"));
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
+
+    #[test]
+    fn render_diff_report_omits_ignored_files() {
+        let _guard = env_lock();
+        let root = temp_dir();
+        fs::create_dir_all(&root).expect("root dir");
+        git(&["init", "--quiet"], &root);
+        git(&["config", "user.email", "tests@example.com"], &root);
+        git(&["config", "user.name", "Rusty Claude Tests"], &root);
+        fs::write(root.join(".gitignore"), ".omx/\nignored.txt\n").expect("write gitignore");
+        fs::write(root.join("tracked.txt"), "hello\n").expect("write tracked");
+        git(&["add", ".gitignore", "tracked.txt"], &root);
+        git(&["commit", "-m", "init", "--quiet"], &root);
+        fs::create_dir_all(root.join(".omx")).expect("write omx dir");
+        fs::write(root.join(".omx").join("state.json"), "{}").expect("write ignored omx");
+        fs::write(root.join("ignored.txt"), "secret\n").expect("write ignored file");
+        fs::write(root.join("tracked.txt"), "hello\nworld\n").expect("write tracked change");
+
+        let report = with_current_dir(&root, || {
+            render_diff_report().expect("diff report should render")
+        });
+        assert!(report.contains("tracked.txt"));
+        assert!(!report.contains("+++ b/ignored.txt"));
+        assert!(!report.contains("+++ b/.omx/state.json"));
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
+
+    #[test]
+    fn resume_diff_command_renders_report_for_saved_session() {
+        let _guard = env_lock();
+        let root = temp_dir();
+        fs::create_dir_all(&root).expect("root dir");
+        git(&["init", "--quiet"], &root);
+        git(&["config", "user.email", "tests@example.com"], &root);
+        git(&["config", "user.name", "Rusty Claude Tests"], &root);
+        fs::write(root.join("tracked.txt"), "hello\n").expect("write tracked");
+        git(&["add", "tracked.txt"], &root);
+        git(&["commit", "-m", "init", "--quiet"], &root);
+        fs::write(root.join("tracked.txt"), "hello\nworld\n").expect("modify tracked");
+        let session_path = root.join("session.json");
+        Session::new()
+            .save_to_path(&session_path)
+            .expect("session should save");
+
+        let session = Session::load_from_path(&session_path).expect("session should load");
+        let outcome = with_current_dir(&root, || {
+            run_resume_command(&session_path, &session, &SlashCommand::Diff)
+                .expect("resume diff should work")
+        });
+        let message = outcome.message.expect("diff message should exist");
+        assert!(message.contains("Unstaged changes:"));
+        assert!(message.contains("tracked.txt"));
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
     }
 
     #[test]
     fn status_context_reads_real_workspace_metadata() {
         let context = status_context(None).expect("status context should load");
         assert!(context.cwd.is_absolute());
-        assert!(context.discovered_config_files >= 3);
+        assert!(context.discovered_config_files >= context.loaded_config_files);
         assert!(context.loaded_config_files <= context.discovered_config_files);
     }
 
@@ -3073,110 +3109,11 @@ mod tests {
             },
         ];
 
-        let converted = super::convert_messages(&messages).expect("messages should convert");
+        let converted = super::convert_messages(&messages);
         assert_eq!(converted.len(), 3);
         assert_eq!(converted[1].role, "assistant");
         assert_eq!(converted[2].role, "user");
     }
-
-    #[test]
-    fn prompt_to_content_blocks_keeps_text_only_prompt() {
-        let blocks = super::prompt_to_content_blocks("hello world", Path::new("."))
-            .expect("text prompt should parse");
-        assert_eq!(
-            blocks,
-            vec![InputContentBlock::Text {
-                text: "hello world".to_string()
-            }]
-        );
-    }
-
-    #[test]
-    fn prompt_to_content_blocks_embeds_at_image_refs() {
-        let temp = temp_fixture_dir("at-image-ref");
-        let image_path = temp.join("sample.png");
-        std::fs::write(&image_path, [1_u8, 2, 3]).expect("fixture write");
-        let prompt = format!("describe @{} please", image_path.display());
-
-        let blocks = super::prompt_to_content_blocks(&prompt, Path::new("."))
-            .expect("image ref should parse");
-
-        assert!(matches!(
-            &blocks[0],
-            InputContentBlock::Text { text } if text == "describe "
-        ));
-        assert!(matches!(
-            &blocks[1],
-            InputContentBlock::Image { source }
-                if source.kind == "base64"
-                    && source.media_type == "image/png"
-                    && source.data == "AQID"
-        ));
-        assert!(matches!(
-            &blocks[2],
-            InputContentBlock::Text { text } if text == " please"
-        ));
-    }
-
-    #[test]
-    fn prompt_to_content_blocks_embeds_markdown_image_refs() {
-        let temp = temp_fixture_dir("markdown-image-ref");
-        let image_path = temp.join("sample.webp");
-        std::fs::write(&image_path, [255_u8]).expect("fixture write");
-        let prompt = format!("see ![asset]({}) now", image_path.display());
-
-        let blocks = super::prompt_to_content_blocks(&prompt, Path::new("."))
-            .expect("markdown image ref should parse");
-
-        assert!(matches!(
-            &blocks[1],
-            InputContentBlock::Image { source }
-                if source.media_type == "image/webp" && source.data == "/w=="
-        ));
-    }
-
-    #[test]
-    fn prompt_to_content_blocks_rejects_unsupported_formats() {
-        let temp = temp_fixture_dir("unsupported-image-ref");
-        let image_path = temp.join("sample.bmp");
-        std::fs::write(&image_path, [1_u8]).expect("fixture write");
-        let prompt = format!("describe @{}", image_path.display());
-
-        let error = super::prompt_to_content_blocks(&prompt, Path::new("."))
-            .expect_err("unsupported image ref should fail");
-
-        assert!(error.contains("unsupported image format"));
-    }
-
-    #[test]
-    fn convert_messages_expands_user_text_image_refs() {
-        let temp = temp_fixture_dir("convert-message-image-ref");
-        let image_path = temp.join("sample.gif");
-        std::fs::write(&image_path, [71_u8, 73, 70]).expect("fixture write");
-        let messages = vec![ConversationMessage::user_text(format!(
-            "inspect @{}",
-            image_path.display()
-        ))];
-
-        let converted = super::convert_messages(&messages).expect("messages should convert");
-
-        assert_eq!(converted.len(), 1);
-        assert!(matches!(
-            &converted[0].content[1],
-            InputContentBlock::Image { source }
-                if source.media_type == "image/gif" && source.data == "R0lG"
-        ));
-    }
-
-    fn temp_fixture_dir(label: &str) -> PathBuf {
-        let unique = SystemTime::now()
-            .duration_since(UNIX_EPOCH)
-            .expect("clock should advance")
-            .as_nanos();
-        let path = std::env::temp_dir().join(format!("rusty-claude-cli-{label}-{unique}"));
-        std::fs::create_dir_all(&path).expect("temp dir should exist");
-        path
-    }
     #[test]
     fn repl_help_mentions_history_completion_and_multiline() {
         let help = render_repl_help();