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implementing-mcp-tools

Guide for exposing PostHog product endpoints as MCP tools. Use when creating new or updating API endpoints, adding MCP tool definitions, scaffolding YAML configs, or writing serializers with good descriptions. Covers the full pipeline from Django serializer to generated TypeScript tool handler.

72

Quality

91%

Does it follow best practices?

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SecuritybySnyk

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The risk profile of this skill

SKILL.md
Quality
Evals
Security

Quality

Content

88%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

A well-structured, highly actionable skill body with executable commands, an explicit pre-scaffold validation checklist, and clear external references. The main room for improvement is splitting detailed reference material into bundle files and trimming some explanatory prose.

Suggestions

Move the YAML key-fields reference and the client character-limit table into a references/ bundle file, keeping SKILL.md as a concise overview with a clearly signaled link.

Tighten the 'Enabling or renaming a tool' prose into a short checklist of deploy-sequencing rules to reduce token overhead.

Add a couple of trigger-term synonyms to the description (e.g. 'MCP server', 'agent tools') to broaden natural-phrase coverage.

DimensionReasoningScore

Conciseness

Dense and technical with no basic-concept padding; every section earns its place, though some explanatory prose (e.g. the enabling/renaming deployment narrative) could be trimmed slightly, placing it above the midpoint but not fully lean.

4 / 5

Actionability

Provides copy-paste executable commands ('pnpm --filter=@posthog/mcp run scaffold-yaml …', 'hogli build:openapi', 'lint-tool-names', '--sync-all') and a concrete YAML example with real fields and file paths, covering the common cases.

5 / 5

Workflow Clarity

Sequenced quick-workflow (steps 1–4) is paired with an explicit pre-scaffold verification checklist (serializer types, @extend_schema, @validated_request) and error-recovery guidance ('empty/wrong schema → fix on the Django side'), with sync-all noted as non-destructive so no cap applies.

5 / 5

Progressive Disclosure

Clear section headers and well-signaled one-level-deep external references (full guide, type-system guide, improving-drf-endpoints skill), but no bundle files exist so detailed reference material (the YAML field reference and client-limit table) is inlined rather than split out, leaving minor organization gaps.

4 / 5

Total

18

/

20

Passed

Description

92%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

A strong, specific description that explicitly answers both what the skill does and when to use it, with concrete trigger phrases and a clearly bounded niche. The only minor gap is trigger-term synonym coverage.

DimensionReasoningScore

Specificity

Lists multiple concrete actions — 'exposing PostHog product endpoints as MCP tools', 'creating new or updating API endpoints', 'adding MCP tool definitions', 'scaffolding YAML configs', 'writing serializers' — covering the full pipeline comprehensively, matching the score-5 anchor.

5 / 5

Completeness

Clearly states what ('Guide for exposing PostHog product endpoints as MCP tools… full pipeline from Django serializer to generated TypeScript tool handler') and an explicit 'Use when…' clause with concrete trigger phrases, matching the score-5 anchor.

5 / 5

Trigger Term Quality

Natural phrases a PostHog engineer would say ('creating new or updating API endpoints', 'scaffolding YAML configs', 'writing serializers', 'MCP tool definitions') give good coverage, but a few natural synonyms/variations (e.g. 'MCP server', 'agent tools') are missing, so it sits above the midpoint rather than at comprehensive.

4 / 5

Distinctiveness Conflict Risk

Tightly scoped to a PostHog-specific niche (PostHog endpoints, MCP tools, Django serializers, TypeScript handlers) with distinct triggers, giving minimal conflict risk with other skills.

5 / 5

Total

19

/

20

Passed

Validation

93%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 15 / 16 Passed

Validation for skill structure

CriteriaDescriptionResult

relative_links

Relative link issues: 1 missing, 1 deeper-than-1-level, 5 suspicious

Warning

Total

15

/

16

Passed

Repository

PostHog/posthog

Path

.agents/skills/implementing-mcp-tools/SKILL.md

Reviewed

Table of Contents

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