Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond the annotations: states the operation is free with no wait ('ready at once'), that the created character is publicly visible on mureka.ai by default unless private:true, how to reverse that later, and the POST endpoint. Cost, latency, and a non-obvious publishing side effect are exactly the traits annotations (readOnly/destructive/idempotent/openWorld) cannot convey.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the core action, then inputs, then outputs/privacy/follow-ups in tight clauses. Every sentence carries information an agent needs; nothing is padding.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For an 8-parameter mutation tool with no output schema, the description covers inputs, the returned identifier, cost/latency, privacy side effects, and the downstream tool. An agent has everything needed to call it and act on the result.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already carries the parameter burden (baseline 3). The description still adds useful meaning: the vocal quality precondition for vocal_id, the mutual exclusivity with song_id, and the behavioral consequence of the private flag.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Specific verb+resource: 'Turn a voice into a reusable singer', with the exact inputs named (vocal_id from mureka_upload_vocal, or song_id). It is unmistakably distinct from siblings like mureka_clone_voice or mureka_upload_vocal without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit prerequisites and routing: source must come from mureka_upload_vocal (~30 s of clear singing) or an existing song, the result feeds mureka_create_song_with_lyrics, and mureka_set_character_private / mureka_list_characters are named for follow-up. It stops short of stating when another tool (e.g. mureka_clone_voice) would be preferred, so no real exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.