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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds genuinely new context beyond that: no account, credential, payment, or live-price side effects, which tells the agent this is an unauthenticated, non-metered read. It does not cover error behavior for unknown 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 short sentences, front-loaded with what is fetched before the side-effect disclaimer. Nothing is redundant or padded.

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?

An output schema exists, so return values need not be explained, and the description covers purpose, cost, and side effects for a single-parameter read. It stops short of noting id validity/error handling or whether fetched content is cached or snapshotted.

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 100% and the id parameter already documents its role with concrete examples (doc:pricing, instrument:crypto:BTCUSD). The description only restates that ids come from search, adding no format or constraint detail beyond the schema, so the baseline 3 applies.

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 (one document or instrument guide), and ties the retrieval to ids produced by the search tool. It differentiates from 'search' by being single-item retrieval, though it does not clarify how it relates to overlapping siblings like get_product_catalog or get_pricing_info.

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?

'Returned by search' establishes the workflow context: use this after a search to pull a specific result by id. The free/read-only framing also signals it is safe to call liberally, but no explicit when-not conditions or named alternatives are given.

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