Save Trajectory

Overview

This skill saves the current Claude Code session's conversation history as a JSON file in OpenAI chat completion format. The trajectory is saved to .evolve/trajectories/ in the project root. This enables trajectory analysis, fine-tuning data collection, and session review.

Workflow

Step 1: Walk Through Conversation Messages

Review all messages in the current conversation from start to finish. For each message, identify its type:

• User text messages
• Assistant text responses (may include thinking)
• Assistant tool calls
• Tool results

Step 2: Convert to OpenAI Chat Completion Format

Convert each message to the appropriate format:

User text message:

{"role": "user", "content": "the user's message text"}

Assistant text response (no thinking):

{"role": "assistant", "content": "the assistant's response text"}

Assistant text response (with thinking):

{"role": "assistant", "content": "the assistant's response text", "thinking": "the thinking/reasoning text"}

Assistant tool call (no visible text):

{
  "role": "assistant",
  "content": null,
  "tool_calls": [
    {
      "id": "tool_call_id_here",
      "type": "function",
      "function": {
        "name": "ToolName",
        "arguments": "{\"param\": \"value\"}"
      }
    }
  ]
}

Assistant tool call with text:

{
  "role": "assistant",
  "content": "text before/after the tool call",
  "tool_calls": [
    {
      "id": "tool_call_id_here",
      "type": "function",
      "function": {
        "name": "ToolName",
        "arguments": "{\"param\": \"value\"}"
      }
    }
  ]
}

Tool result:

{"role": "tool", "tool_call_id": "tool_call_id_here", "content": "the tool output text"}

Important Details

• Tool call arguments must be a JSON string, not a nested object. Use json.dumps() on the arguments object.
• Tool call IDs: Use the actual tool call ID from the conversation. If not available, generate a unique ID like call_001, call_002, etc.
• Multiple tool calls: If the assistant made multiple tool calls in one turn, include all of them in a single assistant message's tool_calls array, followed by separate tool result messages for each.
• Thinking blocks: If the assistant had both thinking and text in the same turn, combine them into one message with both content and thinking fields.

Step 3: Clean Content

Strip <system-reminder>...</system-reminder> tags and their contents from all message content. Use a non-greedy multiline match (e.g., re.sub(r'<system-reminder>[\s\S]*?</system-reminder>', '', text).strip()). If after stripping, a message has empty content and no tool calls, omit it.

Step 4: Build Envelope

Wrap the messages array in a trajectory envelope:

{
  "model": "<model-id-from-session>",
  "timestamp": "2025-01-15T10:30:00Z",
  "messages": [...]
}

• model: Use the exact model ID from the current session's environment context (e.g., the value after "You are powered by the model named …"). Do not hardcode a default — always read it from the session.
• timestamp: Current ISO 8601 timestamp

Step 5: Save via Helper Script

Write the trajectory JSON to a temporary file using the Write tool, then pass the file path to the helper script:

1. Write the JSON to .evolve/tmp/trajectory_input.json using the Write tool (create the directory if needed)
2. Run the helper script with the file path as an argument:

tmp=.evolve/tmp/trajectory_input.json; mkdir -p .evolve/tmp; trap 'rm -f "$tmp"' EXIT; python3 "${CLAUDE_PLUGIN_ROOT}/skills/save-trajectory/scripts/save_trajectory.py" "$tmp"

Important: Do NOT use inline Python scripts, heredocs, or stdin piping to pass the trajectory JSON. Always use the Write tool to create a temp file first. This avoids escaping issues with backslashes, quotes, and newlines in conversation content.

The script will:

• Read the trajectory JSON from the provided file path
• Create the .evolve/trajectories/ directory if needed
• Generate a timestamped filename (trajectory_YYYY-MM-DDTHH-MM-SS.json)
• Write the formatted JSON
• Print confirmation with file path and message count

Example Output

After saving, you should see output like:

Trajectory saved: /path/to/project/.evolve/trajectories/trajectory_2025-01-15T10-30-00.json
Messages: 12

Notes

• This skill captures what's visible in the current conversation context. Very long sessions may have earlier messages compressed or summarized by the system. Include these summarized messages as-is with role: "user" or role: "assistant" as appropriate — do not skip them, since they preserve the conversation flow.
• The trajectory format is compatible with OpenAI chat completion format for downstream tooling.
• Trajectories are saved per-project in .evolve/trajectories/ and can be version-controlled or gitignored as preferred.