google/mantis-reflect
>- Extracts learnings from execution trajectories at the end of a Mantis loop. Use to parse agent conversations, extract successes, failures, and false assumptions, and append them to workspace/learnings.jsonl. Don't use for analyzing source code or writing patches.
npx skills add https://github.com/google/mantis --skill mantis-reflect
Execution Trajectory Analyst. Analyzes the sequence of thoughts, tool calls, and
observations (the "trajectory" or "conversation") of the other Mantis agents.
Extracts valuable insights to prevent future agents from making the same
mistakes.
/mantis-reflectappends structured insights to workspace/learnings.jsonl.
workspace/.mantis_state.json (to track the current loop pass, and to readactive_snapshot.snapshot_id for provenance stamping — see Instructions
step 3). Read this file STATE-RELATIVE under --state_root; never derive
snapshot state by running live VCS.
transcript.jsonl files). The schemaexecution_log_entry defined in schema.json is the normalized
representation. The orchestrator/adapter must normalize raw logs from
unsupported frameworks before passing them, or the reflector must parse
unsupported formats on a best-effort basis.
of absolute file paths to the execution log files (e.g. transcript.jsonl)
for the subagents executed during this round; when provided, use these paths
directly. Do NOT hardcode any single framework's log layout. If no path list
was passed, resolve transcript paths from the ACTIVE harness's own
transcript convention — this is harness-specific and there are several. For
example, Antigravity stores them under
<appDataDir>/brain/<conversation_id>/.system_generated/logs/transcript.jsonl;
other harnesses (e.g. Gemini CLI, the Google ADK, Claude Code) use different
layouts. Antigravity is ONE example among several, not the default. If,
after both routes, no readable transcript exists for a stage that ran this
round, do NOT abort and do NOT silently emit zero learnings — record a
missing-transcript insight per Instructions step 1.
workspace/learnings.jsonl.stage's log is missing, unreadable, empty, or yields zero parseable entries,
this is NOT a fatal error and NOT a reason to stop: continue with the other
stages and record the gap as a trajectory_insight (see Instructions step
1\) so an absent log is never a silent zero-learnings result.
entries in workspace/learnings.jsonl. It should check existing lines in
workspace/learnings.jsonl to ensure it doesn't duplicate the same insight
if retried.
target_entity +insight + source_stage) and treat snapshot as attached metadata, NOT
part of the identity, so a retry within the same pass does not
double-append. Missing-transcript insights (step 1) are de-duplicated the
same way.
LOCATOR RESOLUTION (before reading ANY target code or artifact):
0. ROLE: If this skill NEVER reads target source (report, calibrate, reflect),
you are a FINDINGS-ONLY stage: skip steps 2-6; still read active_snapshot from
state for provenance/annotation; NEVER stop merely because a code root is unset.
1. Determine CODE_ROOT, in this priority order:
a. If --target_root is passed on THIS invocation, CODE_ROOT = --target_root.
It is AUTHORITATIVE and OVERRIDES SNAPSHOT_ROOT and the state fallback
(used when a caller hands you a prepared tree, e.g. a patched shadow).
b. Else if --snapshot_root (or SNAPSHOT_ROOT) is passed, use it.
c. Else read state_root/workspace/.mantis_state.json (state_root from
--state_root if passed, else ./workspace/... relative to the current dir)
-> active_snapshot.root / .snapshot_id / .snapshot_pinned.
d. Else (no arg AND no readable active_snapshot): CODE_ROOT = current directory,
treat snapshot_pinned = false (MODE-OFF). Do NOT stop.
2. SENTINEL CHECK (only if snapshot_pinned is true AND you did NOT take path 1a):
verify CODE_ROOT/.mantis_snapshot_id exists and equals SNAPSHOT_ID. If missing
or different -> STOP "snapshot sentinel mismatch". (A --target_root tree (1a) is
deliberately mutated and is sentinel-EXEMPT.)
3. PATH FIELDS:
- SNAPSHOT-RELATIVE (read under CODE_ROOT): code_paths entries; plan target_files
that are file paths. Strip ONLY a trailing ":<digits>". A code_paths entry
containing "://" is a URL/endpoint, NOT a file read. A code_paths entry that is
NOT of the form <existing-path>:<integer> is a non-source LOCATOR
(symbol/offset/endpoint): only check that the artifact/symbol exists; skip ALL
line-range and line-existence logic.
- STATE-RELATIVE (read/write under state_root/workspace, NEVER prefix CODE_ROOT):
kb_references, repro_file_path, reattack_file_path, helper scripts, report
files, and all state/findings JSON.
4. Never WRITE under CODE_ROOT when snapshot_pinned is true. Any command that
compiles, generates, or writes artifacts MUST run in a PRIVATE SHADOW copy
(mktemp -d from CODE_ROOT), never with cwd=CODE_ROOT. Read-only inspection may
cd into CODE_ROOT.
5. VCS-METADATA CARVE-OUT: history-log extraction and any VCS diff/blame command
run in the LIVE repository root (which still has .git/.hg/.repo), NOT CODE_ROOT
(the snapshot copy strips VCS metadata). Do NOT stop merely because CODE_ROOT
lacks .git/.hg/.repo.
6. Every shell command uses ABSOLUTE paths and sets its own working directory on
that call. Do NOT assume the working directory persists between calls.
Reflector is a FINDINGS-ONLY stage (same class as report and calibrate). Per
Block A step 0 it SKIPS steps 2-6 — it resolves NO CODE_ROOT, checks NO
.mantis_snapshot_id sentinel, and applies NO snapshot-relative path logic —
but it STILL reads active_snapshot from state for provenance and NEVER stops
because a code root is unset or unpinned. Reflector needs only --state_root to
locate workspace/.mantis_state.json, workspace/learnings.jsonl, and the
transcript log files; all of these are STATE-RELATIVE (Block A step 3) and MUST
NEVER be prefixed with CODE_ROOT. Reflector MUST NOT run any live VCS command
(git/hg/repo); its only snapshot signal is active_snapshot.snapshot_id
read from state.
Analyze the execution trajectories of all successfully executed subagents in the
round (every stage that ran: history, summarize, architecture, threat-model,
plan, researcher, dedupe, review, critic, reproduce, chain, patch, calibrate) to
distill what went right and what went wrong.
Execute the reflection stage as follows:
transcript.jsonl files nativelywith read_file, as they can be massive and blow out your context window.
the log files.
parse and filter the logs. For example, write a short Python script or use
jq/grep to extract key events (which should conform to the
execution_log_entry schema; if raw logs from different frameworks are
provided, parse them on a best-effort basis): tool error messages, final
agent summaries, instances where an agent "gave up", or messages indicating
a trust boundary assumption was incorrect.
whose transcript is missing, unreadable, empty, or yields zero parseable
entries, append exactly one trajectory_insight with action: "add",
source_stage: "mantis-reflect",
target_entity: "<stage-name> transcript", and an insight naming the
stage and the reason (e.g. "no transcript file at <path>", "empty log", "0
parseable entries"). Do this BEFORE synthesizing insights, so even a fully
empty round produces auditable output instead of nothing.
parameter, only to realize it was sanitized upstream in another file?
missing library in the sandbox?
specific idiomatic pattern that should be reused?
workspace/learnings.jsonl): For each distinctinsight, append a structured JSON object to workspace/learnings.jsonl.
workspace/learnings.jsonl) {"type": "trajectory_insight", "action": "add | update | remove", "target_entity": "[e.g., auth_module.py or sandbox_env]", "insight": "The researcher assumed input was unsanitized, but it is actually cleansed by the middleware. Do not attempt XSS on this parameter.", "source_stage": "mantis-researcher", "snapshot": "<active_snapshot.snapshot_id from state; omit field entirely if unavailable>"}
Snapshot provenance stamp (never live VCS): Before writing, read
active_snapshot.snapshot_id from workspace/.mantis_state.json
(STATE-RELATIVE, under --state_root). Set the OPTIONAL snapshot field on
EVERY emitted trajectory_insight (including the missing-transcript insights
from step 1) to that value, so each learning is attributable to the pass's
pinned snapshot. Do NOT run git/hg/repo or any live VCS command to
derive it. Backward-compat: if active_snapshot is absent, snapshot is
empty/null, or state is unreadable, OMIT the snapshot field entirely and
proceed (degraded) — never stop and never fabricate an id. snapshot is an
OPTIONAL field: the trajectory_insight sub-schema in schema.json does not
set additionalProperties: false, so existing consumers accept it unchanged.
Ensure the file is appended to, not overwritten. When complete, notify the
user.
Take google/mantis-reflect from the repository into ~/.claude/skills for personal
use, or into .claude/skills inside a project.
The agent identifies a skill by the name field in its header. Two skills with the
same name cannot sit side by side — one of them will be ignored.