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tooluniverse-custom-tool

Add custom local tools to ToolUniverse alongside the 1000+ built-in tools. Covers JSON-config tools (simplest, no code), Python class tools (REST/SOAP/GraphQL APIs, computational logic), and best-practices for return schemas. Use for wrapping new APIs, adding domain-specific computations, or contributing tools to the registry.

Quality

92%

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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.

An exemplary skill body: dense, executable guidance with a clear decision table, complete working examples for every approach, built-in validation and gotcha handling, and bulk reference material correctly externalized into two real one-level-deep reference files. The only improvement space is minor redundancy in the testing section.

Suggestions

In 'Test workspace tools', state the return_schema validation behavior once — the auto-checks bullet and the 'Add test_examples and return_schema' paragraph both explain that 'tu test' validates result["data"] against return_schema.

Consider trimming the duplicated search-example code between the workspace and plugin Python sections to just the key differences, since the 'Key differences' list already enumerates them.

DimensionReasoningScore

Conciseness

The body is code-forward with essentially no explanation of concepts Claude already knows, but the testing section states the return_schema validation behavior twice (in the auto-checks list and again in the guidance below it), and the workspace-vs-plugin Python patterns overlap somewhat — minor trimmable redundancy that fits the 4 anchor rather than the lean 5 anchor.

4 / 5

Actionability

Fully executable, copy-paste-ready examples throughout: complete JSON configs, complete Python classes for both workspace and plugin patterns, and concrete commands ('tu test MyAPI_search '{"q": "test"}'', 'pip install -e /path/to/my_project_root', 'tu info MyAPI_search') covering the common cases.

5 / 5

Workflow Clarity

A decision table routes the user to one of three approaches, each path is sequenced create → test → verify with explicit validation checkpoints ('tu test' auto-checks, 'tu info' to confirm the tool loaded, manual urllib pre-verification of test_examples) and error-recovery guidance for the empty-results gotcha — matching the anchor requiring explicit validation and feedback loops.

5 / 5

Progressive Disclosure

The body is a genuine overview with well-signaled, one-level-deep references — both [references/json-tool.md] and [references/python-tool.md] are real files (315 and 673 lines) that hold the bulk detail — so the split is appropriate and navigation is easy.

5 / 5

Total

19

/

20

Passed

Description

88%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: it uses third person, states concrete capabilities across all three tool-creation approaches, and includes an explicit 'Use for...' clause with natural trigger phrases. The only weaknesses are a few missing natural synonyms and one mildly generic API-wrapping trigger.

DimensionReasoningScore

Specificity

The description lists multiple concrete capabilities — 'Add custom local tools', 'JSON-config tools (simplest, no code)', 'Python class tools (REST/SOAP/GraphQL APIs, computational logic)', 'best-practices for return schemas' — with comprehensive coverage of the skill's scope, matching the top anchor rather than the 4 anchor which requires minor coverage gaps.

5 / 5

Completeness

It explicitly answers both what ('Add custom local tools to ToolUniverse... Covers JSON-config tools... Python class tools...') and when ('Use for wrapping new APIs, adding domain-specific computations, or contributing tools to the registry'), with concrete trigger phrases — a clear match for the top anchor, and it avoids the cap since an explicit 'Use for...' clause is present.

5 / 5

Trigger Term Quality

'wrapping new APIs', 'adding domain-specific computations', and 'contributing tools to the registry' are natural user phrasings, but a few common synonyms (e.g., 'API wrapper', 'REST tool', 'register a tool') are missing, placing it just below the comprehensive-synonym coverage of the 5 anchor.

4 / 5

Distinctiveness Conflict Risk

The ToolUniverse anchoring gives it a clear niche, but the trigger 'wrapping new APIs' is somewhat generic and could overlap with general API-integration skills, matching 'mostly distinct; minor overlap risk' rather than the 5 anchor's 'minimal conflict risk'.

4 / 5

Total

18

/

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

mims-harvard/ToolUniverse

Path

plugin/skills/tooluniverse-custom-tool/SKILL.md

Reviewed

Table of Contents

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