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

Annotations only declare the mutation/safety profile (readOnly=false, non-idempotent, non-destructive). The description adds real behavioral context beyond them: it consumes the account's speech minutes, jobs take 20-90 s, the call blocks up to ~50 s, and the return is either title/duration/mp3 or a jobid. This is exactly the extra context annotations cannot carry.

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 constraints, alternatives, and async behavior. Dense but every clause carries information; slightly packed with the trailing 'POST /speech' detail.

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?

With no output schema, the description still explains the return shape (title, duration, mp3 link, or jobid), the latency envelope, and the cost model. Nothing an agent needs to invoke and interpret the call correctly is missing.

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 baseline is 3, but the description adds meaning by explaining the two mutually-exclusive input modes (text + voice_id, or a multi-speaker conversation array) and where voice_id comes from. It stops short of describing the optional title/account params 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 and resource (turn text into spoken audio) and immediately disambiguates from the nearest sibling with '(not singing)' and 'For songs use mureka_create_song.' An agent can distinguish this from mureka_create_song, mureka_create_song_with_lyrics, and mureka_create_video without opening a 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?

Gives explicit routing: use mureka_create_song for songs, fetch voice_id from mureka_list_voices, and fall back to mureka_get_job when a jobid is returned. The when-to-use and alternative-selection conditions are both stated.

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