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

Annotations already declare destructiveHint=true, idempotentHint=true, and openWorldHint=true, so the risk profile is largely covered. The description adds useful non-obvious context: this is the second half of a deferred-execution flow that previews before approving. It does not disclose that webauthn/auth_token credentials appear to be required, nor whether previously created pending actions expire or are invalidated.

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, mechanism and identifier front-loaded, no filler or restated metadata. Nothing could be trimmed without losing meaning.

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 described. But for a destructive, open-world mutation with an undocumented authentication surface, the description omits what happens after approval, whether credentials are needed, and whether the confirmation is time- or single-use-bound — meaningful gaps for an agent deciding how to call it.

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 0% across 3 parameters, so the description must carry the load. It explains pending_id only implicitly ('by its pending_id'), and says nothing about the webauthn or auth_token parameters, which are the least self-explanatory fields in the schema. Two of three parameters are undocumented in both places.

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 pair ('Preview and approve') and the target resource ('a pending action') keyed by pending_id, which is more informative than the bare name 'confirm'. However, it does nothing to separate itself from the sibling tool 'authorize', which an agent could easily confuse with an approval step.

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?

'Used when a write requires user confirmation before running' gives real context for when the tool applies and implies a prior step created the pending action. But it names no alternative and gives no exclusion — the sibling 'authorize' is never mentioned, leaving the agent to guess which approval path applies.

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