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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. Beyond this, the description adds real value: it discloses the return shape ({ tenant_id, catalog_version, fetched_at }), clarifies the returned value is an 'opaque hash' suitable only for change-detection, and includes a concrete example call. Loses a point only because annotations already carried much of the safety-profile weight.

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?

Organized around a clear narrative arc: what it does, when to use it (vs. alternative), what it returns, and how to call it. Every sentence earns its place, but could be tightened — the example call at the end is slightly redundant given the schema documents the parameter.

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?

This simplification surface (1 param, 100% schema coverage, complete annotations) is comprehensively covered: return type, change-detection semantics, staleness consequence ('you will reference SKUs that no longer exist'), and a copy-pasteable example. No output schema exists, so the explicit return shape disclosure closes the gap.

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% (the sole tenant_id param is fully documented in the schema). The description adds a working example invocation with the parameter, which is helpful, but doesn't reveal non-obvious semantics beyond what the schema already states. This is the textbook baseline-3 case where the schema does the heavy lifting.

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?

Uses a specific verb+resource pattern: 'Return a fingerprint of the current catalog for a tenant' with the clarifying metaphor 'fingerprint' and the purpose 'a cheap way to tell whether the catalog changed.' This clearly distinguishes it from sibling tools like federation_catalog_search_multi (search), federation_catalog_platforms (enumeration), and federation_catalog_agents (agent listing).

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?

Provides rich workflow context: compare the returned version against a previous catalog_search result, re-run catalog_search if they differ before mutating operations like order_create. The 'cheap way' phrasing implicitly contrasts against the more expensive alternative (re-running the search), and the explicit guidance on what to do when versions diverge ('re-run catalog_search to get current product_ids') gives the agent actionable when-to-use direction.

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