Get full lyrics

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

Despite annotations already indicating readOnly, openWorld, and idempotent, the description adds crucial operational behavior: truncation mechanics, 'next_offset' continuation, the legitimate 'no_lyrics' case, and citation expectations. These are not conveyed by the annotations and are essential for correct use.

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?

The description is three sentences, front-loads the primary purpose, and each sentence adds distinct value: fetching source, pagination behavior, edge-case handling, and citation requirement. No wordiness or redundancy.

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 tool with 5 parameters and an output schema, the description covers all essential aspects: how to obtain inputs, how to handle long responses, valid no-lyric edge cases, and user-facing expectations. The output schema covers return fields, so the description need not duplicate them. The sibling reference completes the workflow context.

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 the baseline is 3. The description raises this by explaining how 'offset' relates to 'next_offset' and that lyrics may be truncated, which adds interaction meaning beyond the individual parameter descriptions. It also clarifies that 'url' is from the search tools and that 'id' is preferred.

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?

The description clearly states the verb ('Fetch') and resource ('the full lyrics of one song from lyrics.com'), and specifies the identifying inputs (song id or URL). It also distinguishes itself from the sibling search tools by saying the id/URL comes from those tools.

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?

It explicitly tells when to use the tool (after search_lyrics or search_songs), and provides counter-guidance: 'do not retry' on no_lyrics status. It also explains pagination ('check truncated... use offset') and the requirement to cite source_url and artist.

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