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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds useful behavior the annotations do not: the expected ID prefix schemes (trip:, segment:, travel-document:, document:) and the fact that it returns full text rather than a summary. It omits error behavior for invalid or stale IDs.

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?

Two sentences, no filler, front-loaded with the usage condition followed by the parameter format. Every clause earns its place.

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 one-parameter read tool with annotations covering safety and no output schema, the description supplies purpose, trigger, and ID format. It leaves minor gaps around invalid-ID handling and whether returned text is ever truncated, but nothing essential to invoking it correctly.

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 goes beyond the schema by enumerating the concrete ID formats (trip:{id}, segment:{id}, etc.) that the schema's single `id` string leaves open. That is genuine added meaning for the only parameter.

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 (fetch) and resource (the full text of a specific Tineo search result), and distinguishes itself from the sibling `search` tool by positioning search as the producer of the IDs it consumes. An agent can tell them apart without opening either 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?

"Use this when the user wants the full text for a specific Tineo search result" gives a clear triggering condition, and it names `search` as the source of valid IDs. It does not state any when-not case, but for a simple read tool that is a minor omission.

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