| name | memtrace-episode-replay |
| description | Replay the graph diff of one episode — a single git commit or working-tree save — to inspect what it changed: added/modified/removed symbols and edges. Use when the user asks what one commit or save changed in the graph, why code looks this way, or wants to inspect implementation attempts, reversions, past reasoning, or abandoned approaches across commits and working-tree episodes. Do not use git log or Grep for graph-level episode diffs; Memtrace replays indexed episode records. Do NOT use for module-level summaries or date-range change history — use memtrace-evolution. |
Overview
Replay the graph diff for one episode (a single git commit or working-tree save). Shows which nodes/edges were added, modified, or removed in that episode — not a multi-episode time-range narrative.
Use get_evolution(mode: "recent") to find episode IDs and timestamps, then drill into a specific episode with this tool.
Episode selector — pick one
| Approach | Parameters |
|---|
| Known episode UUID | episode_id |
| Newest episode in repo | repo_id + episode_index: 0 |
| Nth newest | repo_id + episode_index: N |
There is no from / to / include_working_tree on this tool.
Optional filters (large commits)
| Param | Purpose |
|---|
symbol | Scope to one symbol name |
file_path | Substring filter on record paths |
kind | e.g. "Function", "CALLS" |
mode | "graph_summary" for digest on huge commits |
compress | default true — collapse identical-hash modifications |
limit / cursor | Pagination per bucket (default limit 200) |
Full parameter spec for every Memtrace tool: references/mcp-parameters.md (bundled at the memtrace-skills plugin root).
Steps
1. Find the episode to inspect
From get_evolution:
{ "repo_id": "memdb", "from": "7d ago", "mode": "recent", "limit": 20 }
Each entry has episode metadata including id (use as episode_id) and reference_time.
Or use episode_index: 0 for the newest episode without knowing the UUID.
2. Call get_episode_replay
By episode UUID:
{
"episode_id": "550e8400-e29b-41d4-a716-446655440000",
"symbol": "execute",
"file_path": "src/order/service.rs",
"kind": "Function",
"compress": true,
"limit": 200
}
Newest episode, summary first on large commits:
{
"repo_id": "memdb",
"episode_index": 0,
"mode": "graph_summary"
}
3. Interpret the response
| Field | Meaning |
|---|
found | false if episode missing — check _note |
totals | Counts: nodes_added/modified/removed, edges_* |
nodes_added[] etc. | Per-record diffs (paginated) |
page.next_cursor | More records remain — pass as cursor |
For symbol history across many episodes, use get_timeline instead:
{
"repo_id": "memdb",
"scope_path": "OrderService.execute",
"file_path": "src/order/service.rs"
}
Output
get_episode_replay returns the buckets interpreted in step 3:
{
"found": true,
"totals": { "nodes_added": 3, "nodes_modified": 12, "nodes_removed": 1, "edges_added": 7, "edges_removed": 2 },
"nodes_added": [ ],
"nodes_modified": [ ],
"edges_removed": [ ],
"page": { "next_cursor": 200 }
}
Common Mistakes
| Mistake | Reality |
|---|
Passing from / to time window | Not supported — one episode per call |
Expecting narrative_hint / attempted_and_reverted | Not in API — inspect added/modified/removed buckets |
| Unfiltered replay on 10k-symbol commits | Use kind, file_path, symbol, or mode: "graph_summary" first |
| Using this for "what changed last week?" or module summaries | Use memtrace-evolution — get_evolution(from=..., mode: recent) — to list episodes |
