flutter-mcp-boundary-audit

flutter-mcp-boundary-audit is a skill for Claude Code from Arenukvern/mcp_flutter. It costs 92 tokens per session (2,814 once invoked), scanned A, original, MIT.

A review method for checking that registered tools, their descriptions, their input rules, and their execution paths all agree. MCP is a standard for connecting AI agents to tools and data.

In plain words
What is it for?
It helps audit tool registration, discovery, catalogs, schemas, gateways, command aliases, migrations, and Flutter-to-agent integrations.
Why use it?
It finds cases where a tool appears available but accepts different inputs at runtime, or where one access route validates requests and another does not.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the flutter-mcp-toolkit plugin — 14 skills, 1 agent shipped together

Good fit It helps audit tool registration, discovery, catalogs, schemas, gateways, command aliases, migrations, and Flutter-to-agent integrations.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/arenukvern/mcp_flutter/flutter-mcp-boundary-audit
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add Arenukvern/mcp_flutter --skill flutter-mcp-boundary-audit
Clone the repo
git clone --depth 1 https://github.com/Arenukvern/mcp_flutter

Made for: Claude Code.

Or install flutter-mcp-toolkit, the plugin that ships this one along with the rest of its 14 skills, 1 agent.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for flutter-mcp-boundary-audit

README.md
[![agentmods](https://agentmods.dev/badge/skills/arenukvern/mcp_flutter/flutter-mcp-boundary-audit/github.svg)](https://agentmods.dev/skills/arenukvern/mcp_flutter/flutter-mcp-boundary-audit)
Your own site
<a href="https://agentmods.dev/skills/arenukvern/mcp_flutter/flutter-mcp-boundary-audit"><img src="https://agentmods.dev/badge/skills/arenukvern/mcp_flutter/flutter-mcp-boundary-audit/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for flutter-mcp-boundary-audit

Your own site · 80×15
<a href="https://agentmods.dev/skills/arenukvern/mcp_flutter/flutter-mcp-boundary-audit"><img src="https://agentmods.dev/badge/skills/arenukvern/mcp_flutter/flutter-mcp-boundary-audit.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 92 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,814 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00092 $0.02814
Opus 5 $0.00046 $0.01407
Sonnet 5 $0.00018 $0.00563
Haiku 4.5 $0.00009 $0.00281

Measured 10d ago against content hash cbed4901c5ab, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

flutter-mcp-boundary-audit scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugin/skills/flutter-mcp-boundary-audit/SKILL.md · 225 lines

How it starts

The opening of the file, as written. The whole thing — 225 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Contract boundary audit

Skill ID: flutter-mcp-boundary-audit — name is historical; content is repository-neutral. Same workflow applies to MCP stacks, RPC gateways, plugin registries, and OpenAPI-style contracts.

For mcp_flutter, use this skill to audit Flutter adapter parity: fmt_* catalog schemas, CLI exec, VM-service extension gateways, dynamic discovery, migrators, and consumer platform docs. Change app discovery or the Flutter bridge here; change canonical IntentCall registry/session semantics, schema policy, platform projection, or publish behavior upstream.

Find split-brain bugs: what clients see in listings, catalogs, or docs ≠ what runtime enforces on invoke—or validation exists on one gateway only.

Typical symptoms:

  • Advertised required fields differ from what invoke accepts (empty payload succeeds, wrong keys ignored)
  • Host/catalog path validates; in-process or extension path does not (or the reverse)
  • Migrator or codegen rewrites entries with empty or permissive schema placeholders
  • Same logical capability registered twice with different schemas (listing vs invoke, or path A vs path B)
  • Stale docs claim “always permissive” or “no validation” while code is fail-closed

When to run

Trigger (generic) Audit focus
Tool/handler authoring, schema attachment at registration Authoring → discovery payload
Dynamic or plugin registration on the app/runtime side Runtime validate-before-handler
Server registry, forward/dispatch, catalog *_client_tool helpers Registry listing + invoke
Host gateway (VM extension, IPC, HTTP proxy) before delegating to runtime Host validate-before-delegate; fail-closed missing schema
In-process invoke (invokeDirect, browser hook, embedded bridge) Same schema as listing; validate before execute
Entry migrator / codegen from annotated sources Schema preservation, not permissive fallbacks
Shared schema module vs duplicate definitions Dual-path parity
Bridge handlers, non-scalar arguments Encoding (JSON, protobuf, etc.) vs handler expectations
Platform / ADR / registration docs Stale claims vs code

Read the full file on GitHub · 225 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 10d ago First seen · 225 lines · 92 tokens per session scan A cbed4901c5ab

Subscribe to this mod's changes

flutter-mcp-boundary-audit is a skill published in the GitHub repository Arenukvern/mcp_flutter (376 stars, last pushed yesterday), licensed MIT. It adds 92 tokens to every session and 2,814 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.