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

With no annotations, the description carries the disclosure burden; it usefully reveals that the result is wrapped in a proof envelope, uses third-party naming (including dispute_contact_url), and reflects snapshot statistics rather than live data. It does not mention authentication, rate limits, or freshness, but for a zero-parameter read-style rollup these are less critical.

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 compact and front-loads the core return value, then adds the live-stream distinction, third-party naming, and proof envelope. The phrasing 'Third-party-naming —' and the jump from /whales.json to the WebSocket are slightly disjointed, but nothing is redundant.

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 zero-parameter tool with no output schema, the description covers what is returned, the source it mirrors, the live alternative it is not, and the proof envelope wrapper. It does not define 'per-tier × per-filter' or explain the proof envelope's relationship to verify_snapshot_signature, but the invocation surface is minimal.

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?

The tool has zero parameters, so the schema is fully covered and the description does not need parameter-level detail. The baseline for a no-parameter tool 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?

The description names a specific verb and resource: it 'Return[s] the whales_summary rollup cells' with per-tier × per-filter metadata, and further clarifies that it returns generation stats plus body length rather than a live payload. It does not explicitly compare itself to sibling tools like get_whale_events or get_whale_watchlist, so it stops short of full sibling differentiation.

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?

It gives context by pointing to the live WebSocket stream as a different source ('not the live payload') and mentions the mirrored /whales.json endpoint. It does not state explicit alternatives among sibling tools or provide when-to-use/when-not-to-use rules beyond the live-vs-static distinction.

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