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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior. The description adds behavioral context beyond that: ids are opaque, must be passed unchanged, navigation containers have citable=false and child ids rather than source evidence, and historical page identifiers yield migration guidance. This meaningfully informs the agent about edge-case behavior without contradicting any annotation.

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 tight sentences, each earning its place: the first states the core action and source, the second gives the critical pass-through instruction, and the third covers two edge cases. It is front-loaded and free of filler.

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 only one parameter, an existing output schema, and annotations covering safety/idempotency, the description covers all essential operational details: id origin, pass-through requirement, container distinction, and historical-id behavior. Nothing needed for correct invocation 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 description coverage is 0% and the schema only says 'id' is a string. The description fully compensates by specifying the id is opaque, originates from search or document_outline, must be passed unchanged, and clarifying which id types do not correspond to source evidence. This gives the agent a complete mental model of the single 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?

The description states a precise verb-resource pair: 'Fetch original text by an opaque id from search or document_outline.' It clearly defines the input source (ids from two named tools) and contrasts with navigation containers, making it distinguishable from siblings like search and document_outline.

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?

The description gives explicit guidance on what ids to pass: ids from search or document_outline, unchanged, and warns that navigation containers are not source evidence. It also notes that historical page identifiers yield migration guidance, which implicitly tells the agent not to expect source text for those. It lacks an explicit 'when not to use' statement naming alternatives, but the constraints are concrete and actionable.

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