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adding-mcp-store-servers

Add a third-party MCP server (Linear, Notion, GitHub, ...) to the PostHog MCP store catalog. Use when asked to "add X to the MCP store", expand the MCP server marketplace, or fix a broken catalog entry. Covers finding the vendor's remote MCP endpoint, probing it (handshake, OAuth discovery, DCR), authoring the catalog entry in products/mcp_store/backend/catalog.py, verification tiers, and the operator handoff for servers without Dynamic Client Registration.

77

Quality

97%

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The risk profile of this skill

SKILL.md
Quality
Evals
Security

Quality

Content

92%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 dense, highly actionable runbook for a real multi-step production workflow, with validation checkpoints, error-recovery paths, and guardrails ('What not to do') all present. The only notable gap is the absence of a concrete example catalog entry in the authoring step, which keeps actionability just short of fully copy-paste ready.

Suggestions

Include a minimal example entry (name/description/category/icon_domain/docs_url, or an excerpt of an existing one) in the 'Author the entry' step so the exact code shape is visible without opening catalog.py.

Show a short sample of the probe's JSON verdict so the quoted field names (auth_flavor, reachable, passed_activation_gate) can be matched directly against real output.

Add one line for the failure path of step 5 — which entry fields to fix when test_catalog_entries_are_valid fails and to re-run — to make the validate→fix→retry loop fully explicit.

DimensionReasoningScore

Conciseness

Every section carries PostHog-specific knowledge Claude cannot infer — sync semantics ('sync_mcp_server_templates upserts entries into MCPServerTemplate rows... there are no data migrations, no icon assets'), probe verdict meanings, and logo.dev icon resolution. There is no filler and no explanation of concepts Claude already knows; the intro's three sentences both establish the mental model and pre-empt three wrong assumptions. Not score 4 because no section could be trimmed without losing operative detail.

5 / 5

Actionability

Concrete executable guidance throughout: the probe command ('DEBUG=1 python manage.py probe_mcp_server https://mcp.example.com/mcp'), the test command ('hogli test products/mcp_store/backend/test/test_catalog_sync.py'), two concrete icon-verification methods, and a paste-ready operator checklist. Not score 5 because the 'Author the entry' step describes the fields but never shows an actual entry snippet, leaving the entry's code shape to be inferred from catalog.py; not score 3 because every command given is fully executable and each probe verdict maps to a specific action.

4 / 5

Workflow Clarity

Six explicitly sequenced steps with validation at every risky point: probe verdict logic with a stop-and-re-research error path ('speaks_mcp: false → Stop and re-research' with one precisely-described exception), a Gate B real-install verification with recorded tiers, a test that 'catches malformed entries... before they hit production', and an operator checklist. This matches the anchor requiring explicit validation steps, error-recovery feedback, and checklists; there are no missing checkpoints that would drop it to 4.

5 / 5

Progressive Disclosure

Well-organized single-file skill (Read first, Workflow, Operator checklist, What not to do) with clearly signaled one-level-deep pointers to repo files ('products/mcp_store/README.md — the catalog pipeline, sync semantics, and operator runbook', catalog.py, probe.py). Nothing that belongs in a separate file is inlined — the operator checklist is inline correctly since it must be pasted into a PR — and navigation is trivial. No organization gaps that would drop it to 4.

5 / 5

Total

19

/

20

Passed

Description

100%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.

An exemplary description: third-person, specific, and dense with concrete actions, and it includes an explicit 'Use when' clause quoting natural user phrasing with named vendors and both the add and fix use cases. No vague or padded language; distinctiveness is strong.

DimensionReasoningScore

Specificity

Lists multiple specific concrete actions with comprehensive coverage: 'finding the vendor's remote MCP endpoint, probing it (handshake, OAuth discovery, DCR), authoring the catalog entry in products/mcp_store/backend/catalog.py, verification tiers, and the operator handoff for servers without Dynamic Client Registration' — including an exact file path. Not score 4 because coverage spans the full task lifecycle with no minor gaps.

5 / 5

Completeness

Explicitly answers both what ('Add a third-party MCP server... to the PostHog MCP store catalog', with the covered sub-tasks enumerated) and when ('Use when asked to "add X to the MCP store", expand the MCP server marketplace, or fix a broken catalog entry') with concrete trigger phrases. Both clauses match the top anchor exactly.

5 / 5

Trigger Term Quality

Quotes the literal user phrasing ('add X to the MCP store') plus natural variations users would actually say: 'expand the MCP server marketplace' and 'fix a broken catalog entry', alongside concrete vendor names (Linear, Notion, GitHub). Coverage of add/expand/fix synonyms is comprehensive; not score 4 because no commonly-used natural phrasing for this task is missing.

5 / 5

Distinctiveness Conflict Risk

Clear niche: the PostHog MCP store catalog, with a specific repo path and named vendors. Triggers like 'add X to the MCP store' would not naturally fire for any other skill, and the body's scope ('Only hosted (remote) MCP servers belong in the catalog') further delimits it. Minimal conflict risk.

5 / 5

Total

20

/

20

Passed

Validation

100%

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

Validation — 16 / 16 Passed

Validation for skill structure

No warnings or errors.

Repository

PostHog/posthog

Path

.agents/skills/adding-mcp-store-servers/SKILL.md

Reviewed

Table of Contents

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