mcpbeat

Shadow Frog Update

microsoft/shadow-frog-update

>- Update the shadow knowledge base after code changes and from conversational insights. Detects what changed via git diff, refreshes per-file shadows, captures knowledge shared by the user during the session, and updates cross-cutting discoveries. Invoke manually with /shadow-frog-update; the preToolUse hook will remind the agent when the shadow is behind HEAD.

2k tokens
context cost
the whole folder, loaded on every use
1
files
instructions only
0
copies elsewhere
how many repositories repackaged it
17
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/microsoft/ShadowFrog --skill shadow-frog-update

The instruction itself

13 sections, as written by the author

ShadowFrog Update

Updates .shadow/ from two sources: code changes (git diff) and conversational

knowledge (what the user said during the session). Prerequisite: .shadow/ exists.

Triggers

  • Hook reminder: preToolUse injects a staleness warning when

.shadow/_meta/state.json#last_commit differs from HEAD. The hook

only reminds — it does NOT auto-run update.

  • Manual: user invokes /shadow-frog-update

Phase 1: Detect Changes

# Read last_commit defensively: it may be missing, or the literal "none"
# when init ran without git (e.g. inside a container). `git diff none HEAD`
# would abort with "fatal: bad revision 'none'", and a missing key would
# make $LAST_COMMIT empty so `git diff HEAD` silently reports the wrong set.
LAST_COMMIT=$(python3 -c "import json,sys; print(json.load(sys.stdin).get('last_commit','none'))" < .shadow/_meta/state.json 2>/dev/null || echo "none")
if git rev-parse --verify "$LAST_COMMIT" >/dev/null 2>&1; then
    git diff --name-only "$LAST_COMMIT" HEAD   # committed changes since last update
else
    echo "WARNING: state.json has no usable last_commit — falling back to a full re-scan."
fi
git diff --name-only HEAD                       # uncommitted changes
git diff --name-only --cached                   # staged changes

Categorize: modified, added, deleted, renamed.

Phase 2: Update Per-File Shadows (Symbol-Level)

For each changed file, update its shadow at the symbol level:

  • Added symbols → add new ## section
  • Removed symbols → mark section as REMOVED, keep discoveries for history
  • Renamed symbols → update heading, preserve discoveries
  • Modified symbols → check if discoveries still hold

Lightweight update (auto/hook): re-extract symbols, update headings, flag stale.

Deep update (manual/dream): read diffs, generate new discoveries, verify existing ones.

Phase 3: Capture Conversational Knowledge

When the user shares knowledge during the session, write it immediately.

Do not batch for later.

Signals to capture:

| Signal | Example | Category |

|--------|---------|----------|

| Warning | "Don't change the retry logic, it's subtle" | warning |

| Design intent | "We use this pattern because the API is unreliable" | intent |

| History | "We tried caching here but it caused stale reads" | history |

| Gotcha | "This looks wrong but matches the tax authority spec" | warning |

| Deprecation | "This module is being replaced by v2/" | intent |

| Contract | "The 30s timeout matches our SLA" | contract |

| Convention | "Always use the helper in utils.py, not raw SQL" | convention |

Write as:

- <user's words, as close to verbatim as possible>
  _(verified, source: user)_

For knowledge emerging from collaborative work (debugging, refactoring, test failures):

- <what was discovered and how>
  _(verified, source: interaction)_

Anchor to the specific file::symbol. source: user and source: interaction

are always verified.

Auto-Placement

Users will not specify where to store their knowledge. You must find the

correct location. Procedure:

  • Parse the user's statement for code references — file names, function names,

class names, module names, variable names, error messages, CLI flags.

  • If the knowledge is a project-wide preference or convention with no code

references (e.g., "always use snake_case", "no backward compatibility",

"prefer small PRs") → write to _prefs.md.

  • If explicit references found → look up those file::symbol paths in

_index.md and the corresponding shadow files.

  • If no explicit references → use context:
  • What file is the user currently viewing or editing?
  • What files were recently modified in this session?
  • Search shadow files: grep -rl "<keyword>" .shadow/ --include="*.md"
  • If multiple candidate locations → pick the most specific symbol that the

knowledge applies to. Prefer a single file::symbol over file-level.

  • If the knowledge spans 3+ files → create a _cross/<slug>.md

entry and add back-pointers to each involved file's ## Cross-References.

For 2-file discoveries, use per-file entries with Also involves: instead.

  • If no matching location exists (e.g., the user mentions a concept not yet in

the shadow) → place at the file-level ## File-Level section of the most

relevant file, or create a new _cross/ entry for repo-wide knowledge.

Never ask the user "where should I put this?" — always resolve placement yourself.

Phase 4: Extract Session Insights

At session end or manual trigger, review the session for:

  • Files modified and why
  • Patterns revealed by the changes
  • Unrecorded conversational knowledge (user statements not yet shadowed)
  • Cross-cutting discoveries (create in _cross/<slug>.md if 3+ files involved)

Phase 5: Handle Structural Changes

Added files:

  • Check .shadow/.shadowignore — skip if the file matches an ignore pattern
  • Create .shadow/<path>/<file>.md with symbol-organized template
  • Add ## Cross-References section
  • Add to _index.md

Deleted files:

  • Add ORPHANED marker to shadow header
  • Keep shadow (discoveries explain history)
  • Mark [REMOVED] on any _cross/ refs pointing to this file
  • Update _index.md

Renamed files:

  • Move .shadow/<old>.md to .shadow/<new>.md
  • Update all _cross/ Refs: entries (old path → new path)
  • Update all Also involves: in other per-file shadows
  • Update _index.md
  • Preserve all discoveries

Phase 6: Verify and Dedup

Follow the dedup and writing rules in /shadow-frog — read before

write, merge or update existing entries, fix bad format in place.

Verify exploration discoveries using the observe-based or do-based

methods in /shadow-frog § Verification. source: user and

source: interaction → always verified; only re-verify if the

underlying code changes.

Phase 7: Verify Reference Integrity

Check the five core invariants (full 7-invariant set in /shadow-frog):

  • Every _cross/<slug>.md ref has a back-pointer in per-file ## Cross-References
  • Every ## Cross-References entry has a corresponding _cross/<slug>.md
  • No duplicate cross-cutting filenames
  • All Also involves: use file::symbol notation
  • No duplicate discoveries (same behavioral claim at same symbol)

Repair any violations before proceeding.

Phase 8: Update Metadata

Preserve dream_cycles_completed from the existing state — only dream-reconcile.py increments it.

{
  "version": 1,
  "initialized_at": "<preserved>",
  "last_update_at": "<now ISO>",
  "last_commit": "<full 40-char HEAD SHA>",
  "last_update_type": "init|auto|manual|dream|meditate",
  "total_files": N,
  "total_symbols": N,
  "total_discoveries": N,
  "dream_cycles_completed": <preserved>
}

Refresh _index.md with current counts.

Discovery Writing Rules

See /shadow-frog § Discovery Format for the verbatim per-file,

cross-cutting, and preference formats. Rules to keep in mind during

update sessions:

  • Be behavioral: "silently returns None on expired tokens" not "handles token expiration"
  • source: user and source: interaction → always verified, use user's own words
  • source: exploration → mark uncertain unless verified by code reading or tests
  • If 3+ files involved → create in _cross/<slug>.md instead, add back-pointers
  • If project-wide preference with no file reference → write to _prefs.md
  • Slug naming: kebab-case derived from title (e.g., "Token expiry config split" → token-expiry-config-split.md)

Staleness Rules

  • Symbol modified → check if discovery still holds
  • Symbol renamed → move discoveries to new heading
  • Symbol removed → mark section REMOVED, keep discoveries
  • source: user discoveries → only mark stale if symbol completely removed

How to use it

Copy the folder

Take microsoft/shadow-frog-update 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.