CtrlK
BlogDocsLog inGet started
Tessl Logo
SkillPublic

cooper-email

Give Claude its own email inbox with Cooper Email to send, receive, reply, and wait for replies or verification codes over a hosted MCP server or HTTP. Use when the user wants the agent to have its own email address, not access to the user's mailbox.

Quality

91%

Does it follow best practices?

Run evals on this skill

Adds up to 20 points to the overall score

View guide
SecuritybySnyk

Low

Low-risk findings worth noting

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 highly operational skill body: executable commands for every operation, explicit human-approval checkpoints with unattended-run fallbacks, and real error-recovery guidance. The only soft spots are repeated approval-gate phrasing across sections and a monolithic single-file layout that could split the safety procedures from the API reference.

DimensionReasoningScore

Conciseness

The body is dense and operational — complete curl commands, MCP tool names, error codes — with almost no explanation of concepts Claude already knows; the only trimmable fat is the approval-gate language repeated across 'Before Sending', 'Links and Codes', 'Receive and wait', and 'Tips' (e.g., 'wait for a yes before opening the link or using the code' appears three times). This fits 'efficient; minor instances of over-explanation that could be trimmed' rather than the every-token-earns-its-place anchor.

4 / 5

Actionability

Fully executable, copy-paste-ready curl commands for onboarding, sending (with Idempotency-Key), listing, waiting, and replying; named MCP tools for each operation; a worked user/agent example; and concrete error semantics ('HTTP 409 inbox_exists means the name is taken', 'timed_out: true means nothing arrived; call again') covering the common cases.

5 / 5

Workflow Clarity

The 'What This Skill Does' section sequences the full flow (reuse/create key → connect MCP → send → read → wait → reply) and the required sections add explicit validation checkpoints with feedback loops: preview-then-explicit-yes before every irreversible send, draft-and-stop fallbacks for unattended runs, the 409/timeout recovery paths, and the untrusted-data handling for links and codes. This matches the 'clear sequence with explicit validation steps; feedback loops for error recovery' anchor.

5 / 5

Progressive Disclosure

A single well-organized SKILL.md (~112 lines) with clear section headers and one-level-deep external pointers (llms.txt, the GitHub repo) that are clearly signaled in Tips; however, everything lives inline in one file with no split of the safety procedures from the API quick-reference, so it sits at 'good structure; most content appropriately placed; minor organization gaps' rather than the well-split five.

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 description: concrete capability list, an explicit 'Use when' trigger clause, and an explicit boundary against the nearest competing use case (accessing the user's own mailbox). Voice is neutral imperative with no first/second person. Only gap is a few missing natural synonyms for codes/replies.

DimensionReasoningScore

Specificity

The description lists multiple concrete actions — 'send, receive, reply, and wait for replies or verification codes' — plus the delivery mechanisms ('hosted MCP server or HTTP'), matching the comprehensive multi-action anchor rather than the score-4 anchor's 'minor gaps in coverage'.

5 / 5

Completeness

It explicitly answers both questions: the 'what' is 'Give Claude its own email inbox with Cooper Email to send, receive, reply, and wait for replies or verification codes over a hosted MCP server or HTTP' and the 'when' is the explicit 'Use when the user wants the agent to have its own email address, not access to the user's mailbox' clause — a clear, concrete trigger phrase.

5 / 5

Trigger Term Quality

Natural terms like 'email inbox', 'email address', 'verification codes', 'mailbox', and 'replies' are present and would be said by users, but common synonyms such as 'confirmation code', 'OTP', or 'check email' are missing, fitting 'good keyword coverage; a few natural terms missing' rather than comprehensive synonym coverage.

4 / 5

Distinctiveness Conflict Risk

It carves out a clear niche — the agent's own inbox — and explicitly disambiguates with 'not access to the user's mailbox', minimizing overlap with generic mail-access skills; this matches the 'clear niche with distinct triggers; minimal conflict risk' anchor.

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

frontmatter_unknown_keys

Unknown frontmatter key(s) found; consider removing or moving to metadata

Warning

Total

15

/

16

Passed

Repository

davepoon/buildwithclaude

Path

plugins/all-skills/skills/cooper-email/SKILL.md

Reviewed

Table of Contents

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.