mcpbeat

Mantis Summarize

google/mantis-summarize

>- Pre-processes the repository by generating security-focused summaries (mantis-summary.md) for each directory to make planning and research more efficient. Use when starting a review campaign to map the codebase before threat modeling and planning. Don't use for executing code reviews, writing test scripts, or patching code.

2k tokens
context cost
the whole folder, loaded on every use
1
files
instructions only
0
copies elsewhere
how many repositories repackaged it
707
stars on the repo
on the repository, not the skill itself

Install

one command, takes just this skill from the repository
npx skills add https://github.com/google/mantis --skill mantis-summarize

What it tells the agent to use

found in the instruction text
Bash runs shell commands — read the instruction before connecting

The instruction itself

6 sections, as written by the author

Summarizer (/mantis-summarize)

System Goal

Repository Mapper. Automates the generation of security-focused, deterministic

summaries of directory contents to reduce token overhead for downstream planning

and research stages.

Command Definition

  • Command: /mantis-summarize
  • Description: Pre-processes the repository by generating security-focused

summaries (mantis-summary.md) for each directory to make planning and

research more efficient.

  • Arguments (optional; supplied by the orchestrator, consumed by Block A):

--snapshot_root/--snapshot_id/--state_root. In PINNED mode, source is

read under CODE_ROOT but summaries are skipped (see Output location). All

absent → MODE-OFF (in-tree summaries, as today).

Input/Output Contract

  • Reads:
  • workspace/.mantis_state.json (to track current loop pass).
  • Codebase directories and source files (excluding node_modules, vendor,

.git, build outputs, and tests/).

  • Child directory summaries (mantis-summary.md files from subdirectories).
  • workspace/historical_learnings.jsonl (optional, to enrich summaries).
  • Writes:
  • Traversal script to workspace.
  • MODE-OFF: mantis-summary.md in each source directory (as today). PINNED:

skipped (see Output location).

  • Preconditions:
  • Source files and directory structure must be present.
  • Idempotency Guarantee:
  • Deterministically overwrites existing mantis-summary.md files in-place

with updated rollups.

Instructions

Step 0: Locator Resolution + output location (run first)

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.

Output location (MANDATORY):

  • PINNED mode (snapshot_pinned true): summaries are skipped this pass. In

PINNED mode, CODE_ROOT is read-only (Block A step 4), and consumers (plan,

history, researcher) read mantis-summary.md from the source directory in the

code tree — not from a state-relative mirror. Writing to a mirror that no

consumer reads would silently waste the work. Do NOT write any

mantis-summary.md files in PINNED mode. (If a future change wires consumers

to the mirror + re-maps via a provenance marker, this can be revisited; for

now, PINNED-mode summaries are inert.)

  • HALT mode (active_snapshot present + snapshot_pinned=false): behave as

MODE-OFF (write mantis-summary.md into each source directory). The snapshot

is not read-only (no immutable copy was pinned), so writing into the tree is

safe.

  • MODE-OFF (no active_snapshot — today's default): behave exactly as today —

write mantis-summary.md into each source directory.

  • In all modes except PINNED, mantis-summary.md files must remain invisible to

every VCS dirty check and be deleted from the target tree before any sync (the

meta-agent enforces this in Block C STEP 0). Never let a summary make the tree

look dirty.

Your task is to write and execute a script that will traverse the repository

directory tree and create a mantis-summary.md file in each directory

containing source code.

This is an optional pre-processing phase designed to drastically reduce the

context window size required for the strategist (/mantis-plan), and provide a

quick reference map for researchers (/mantis-researcher).

Execute the summarize stage as follows:

  • Write the Traversal Script (Bottom-Up Hierarchical): Write a script

(e.g., Python or bash) in your workspace that walks the repository directory

tree using a bottom-up (post-order) traversal.

  • The script must ignore non-source-code directories such as node_modules,

vendor, .git, build outputs, and tests/.

  • By traversing bottom-up, the script ensures that subdirectories are

summarized *before* their parent directories.

  • When analyzing a directory, the script should pass the LLM the local source

files in that directory PLUS the mantis-summary.md files of its

immediate subdirectories. Do not pass the raw source files of

subdirectories to the parent.

  • When analyzing very large directories, context window size might become a

problem. Instead of passing files and directory summaries in bulk, generate

per-file summaries or operate in more efficient chunks to avoid passing too

many tokens for the LLM to handle.

  • Generate the Security Summary (Map-Reduce): The script should read

workspace/historical_learnings.jsonl (if it exists) to check for past

vulnerabilities and security fixes associated with files in the current

directory, and pass them in context. The script should instruct the LLM or

agent tool to generate a concise, security-focused summary of the directory.

To keep token lengths reasonable at higher levels of the directory tree, the

LLM should abstract away lower-level details, focusing on the rolled-up

architecture. The prompt used by your script should ask for:

  • Core Components: What are the primary files and subdirectories, and

what do they do?

  • API Endpoints & Exports: What functions or classes are exposed to other

modules?

  • Trust Boundaries & External Inputs: Does this directory handle

untrusted data, network requests, or user input?

  • Sensitive Operations: Are there parsers, cryptographic functions, or

memory management operations?

  • Historical Vulnerabilities & Fixes: What files or components in this

directory have historical vulnerabilities or security-related fixes

recorded in workspace/historical_learnings.jsonl? Summarize the past

fixes, components affected, and vulnerability classes to highlight past

regressions or recurring weaknesses.

The summary must be a reasonable size to incorporate into work on larger

problems, so aim for several thousand words or fewer.

  • Output to mantis-summary.md: In MODE-OFF (or HALT), write

mantis-summary.md into the corresponding source directory (overwrite if

present). In PINNED mode, do NOT write — summaries are skipped this pass (see

Output location above). Never write into the read-only snapshot.

  • Execute the Script: Run the script you just wrote to generate all the

summaries across the repository. Wait for it to finish successfully.

  • Complete: Summaries are now generated. Notify the user.

When complete, notify the user.

How to use it

Copy the folder

Take google/mantis-summarize from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

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.