toolpath-gemini

Derive Toolpath provenance documents from Gemini CLI conversation logs.

When Gemini CLI writes your code, the conversation — the reasoning, the tool calls, the sub-agent delegations — is the provenance. This crate reads those conversations directly from ~/.gemini/tmp/... and maps them to Toolpath documents so every AI-assisted change has a traceable origin.

Overview

Reads Gemini CLI conversation data from ~/.gemini/tmp/<project>/chats/ and provides:

• Conversation reading: Parse the JSON chat files into typed structures
• Query: Filter and search messages by role, tool use, text content
• Derivation: Map conversations to Toolpath Path documents
• Watching: Monitor chat files for live updates (feature-gated)

Mapping

Derivation

use toolpath_gemini::{GeminiConvo, derive::{DeriveConfig, derive_path}};

let manager = GeminiConvo::new();
let convo = manager.read_conversation(
    "/Users/alex/project",
    "session-uuid",
)?;

let config = DeriveConfig::default();
let path = derive_path(&convo, &config);
# Ok::<(), Box<dyn std::error::Error>>(())

Reading conversations

use toolpath_gemini::GeminiConvo;

let manager = GeminiConvo::new();

// List projects
let projects = manager.list_projects()?;

// List sessions for a project
let sessions = manager.list_conversations("/Users/alex/project")?;

// Read a full session (main chat + all sub-agent chats)
let convo = manager.read_conversation(
    "/Users/alex/project",
    "session-uuid",
)?;

// Most recent conversation
let latest = manager.most_recent_conversation("/Users/alex/project")?;

// Lightweight metadata, including the first user-prompt text as a
// human-readable title for picker UIs.
for meta in manager.list_conversation_metadata("/Users/alex/project")? {
    println!(
        "{} ({}msgs): {}",
        meta.session_uuid,
        meta.message_count,
        meta.first_user_message.as_deref().unwrap_or("(no prompt)"),
    );
}
# Ok::<(), Box<dyn std::error::Error>>(())

Provider-agnostic usage

This crate implements toolpath_convo::ConversationProvider, so consumers can code against the provider-agnostic types instead of Gemini-specific structures.

use toolpath_gemini::GeminiConvo;
use toolpath_convo::ConversationProvider;

let provider = GeminiConvo::new();
let view = provider.load_conversation("/path/to/project", "session-uuid")?;

for turn in &view.turns {
    println!("[{}] {}: {}", turn.timestamp, turn.role, turn.text);
    for tool_use in &turn.tool_uses {
        if let Some(result) = &tool_use.result {
            println!("  {} -> {}", tool_use.name, if result.is_error { "error" } else { "ok" });
        }
    }
}

Tool classification

Gemini CLI tool names are mapped to ToolCategory:

Unrecognized tools get category: None — consumers still have name and input.

Sub-agent delegations

Sub-agent invocations are stored as sibling chat files (kind: "subagent") in the same session UUID directory. When you load a conversation, those sub-agent chats are folded into DelegatedWork on the parent task tool invocation with turns populated (unlike toolpath-claude, which leaves sub-agent turns empty because they live in separate session files).

Environment context

Each turn's EnvironmentSnapshot.working_dir is populated from the chat file's top-level directories[0].

Token usage

Per-turn TokenUsage includes:

• input_tokens ← tokens.input
• output_tokens ← tokens.output
• cache_read_tokens ← tokens.cached
• cache_write_tokens → None (Gemini doesn't expose this)

ConversationView.total_usage aggregates across all turns.

Provider-specific metadata

Gemini log entries often carry extra fields (thoughts, tokens.tool, tokens.total, kind, summary) that don't map to the common schema. These are forwarded into Turn.extra["gemini"] so trait-only consumers can access them without importing Gemini-specific types.

Round-trip fidelity

The crate exposes three progressively lossy views of a conversation:

For a true round-trip — Gemini → Toolpath → Gemini — stay at the ChatFile level:

use toolpath_gemini::{ChatFile, GeminiConvo};

let raw = std::fs::read_to_string("/path/to/chats/session-X.json")?;
let chat: ChatFile = serde_json::from_str(&raw)?;
// ... inspect or modify chat ...
let back = serde_json::to_string(&chat)?; // byte-equivalent to `raw` (modulo key order)

Guarantees baked in:

• Every unknown field — top-level or per-message — rides through via #[serde(flatten)] extra: HashMap<String, Value>. Future schema additions survive unchanged.
• GeminiRole preserves unknown role values ("plan", "system", etc.) via Other(String); known values (user/gemini/info) deserialize into typed variants.
• ToolCall.result_display is Option<Value>, so Gemini's structured payloads (dict-with-fileDiff, nested ANSI-styled arrays) round-trip opaquely.
• Optional list fields (directories, thoughts, toolCalls) use Option<Vec<T>> so we distinguish absent from present-but-empty.

Feature flags

Part of Toolpath

This crate is part of the Toolpath workspace. See also:

• toolpath -- core types and query API
• toolpath-convo -- provider-agnostic conversation abstraction
• toolpath-claude -- Claude conversation provider
• toolpath-git -- derive from git history
• toolpath-dot -- Graphviz DOT rendering
• path-cli -- unified CLI (cargo install path-cli)
• RFC -- full format specification