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

Beyond the annotations (readOnlyHint, idempotentHint, destructiveHint), the description adds meaningful context: it returns 'additive curated constituent overlays grouped by source date', preserves the 'evidence boundary' of persisted registry rows, and explicitly states it does not fetch live exchange data, place trades, or mutate recorder state.

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-loaded with the core purpose, and every sentence conveys essential information without redundancy or fluff.

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?

Given the read-only nature, the presence of an output schema, and rich annotations, the description covers the necessary behavioral constraints, parameter options, and evidence-boundary nuance. It is complete for an agent to select and invoke the tool 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 description coverage is 100%, so each parameter is already documented. The description restates required product and optional filters (source_date, source_date_from/to, mode, limit, offset) but does not add meaning beyond what the schema already provides.

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 specific verb+resource: 'retrieve persisted constituent registries for one Coinbase thematic or index perp product'. It also distinguishes itself by clarifying these are 'persisted registry rows rather than live exchange-native constituent APIs', which differentiates it from sibling 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?

The description clearly establishes when to use the tool ('Use this read-only tool...') and excludes live data fetching, trade placement, and recorder mutation. However, it does not explicitly name alternative tools for those use cases, so it falls short of a 5.

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