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

Annotations cover the safety profile (readOnly, non-destructive), and the description goes well beyond them: it discloses mode fallback behavior, that response.mode reports which path ran, byte-exact post-verification of quotes, and the billing/metering model (free without matching claims, receipts and model drafts metered). This is unusually rich behavioral context; it stops short of explaining return structure or rate limits explicitly.

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?

It is front-loaded with 'Extractive by default', which is good, but the single dense paragraph is packed with jargon ('1.58-bit model', 'Signed citation receipt', 'stitched') that impedes quick scanning. Every sentence carries some payload, yet the structure is heavier than needed.

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 no output schema, the description must convey the return shape; it partially does (response.mode, saves token estimate, source list with byte spans), which is helpful. But it omits explanation of several payment/session parameters and does not cover error or fallback edge cases fully, so it is adequate rather than complete.

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 only 29% across 7 parameters. The description partially compensates by explaining mode (extractive vs generative, response.mode), receipts (metered vs free), and slugs indirectly, but x_payment, work_token, max_claims, and question constraints go undocumented in both schema and prose — a significant gap for a 7-param tool.

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 (answer) and resource (verified claims) and explains the mechanism: extractive by default, quotes stitched with connectives and [n] markers, receipts per claim. It is clear enough to distinguish 'answer' as a quote-assembly tool, though it never contrasts itself with the near-identical sibling 'ask'.

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 implies usage with 'One call in place of a crawl-and-summarise loop' and defines free/metered conditions, which is real context. However, there is no explicit when-not guidance and no comparison to siblings like ask or research, leaving the agent to infer the right choice.

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