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

Annotations cover non-readonly/non-idempotent, and the description adds cost (12 Gold per song), latency (~45-90 s), wait behavior (up to ~50 s), and dual return paths (songs inline or jobid). This is well beyond annotation content.

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?

Three dense sentences: purpose, routing alternatives, async behavior and return, then endpoint. Nothing redundant, front-loaded with the action.

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 a 3-param generation tool with no output schema, it conveys cost, latency, wait cap, return shape, and the fallback job path – everything needed to call it and know what to expect.

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 coverage is 100%, so parameter meaning is already in the schema. The description adds model/cost hint (V9.5: 12 per song) and confirms lyrics are auto-written from prompt, but no extra syntax or constraints beyond the schema.

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?

States a specific verb+resource: 'Generate two songs from a text description; Mureka writes the lyrics,' and explicitly distinguishes from siblings mureka_create_song_with_lyrics and mureka_create_instrumental.

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 routing: 'For your own lyrics, a voice, a character or a reference track use mureka_create_song_with_lyrics, for no vocals mureka_create_instrumental.' Also names mureka_get_job as the continuation for the async jobid path.

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