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

Annotations already declare destructiveHint=true, idempotentHint=true. The description adds useful context beyond those annotations: requires Startup or higher, both read and write consent, a stable idempotency key, exact-intent confirmation, and that it approves the exact current revision. It does not describe what gets destroyed/changed downstream, but it goes beyond the structured metadata.

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?

Three sentences, front-loaded with what is approved, then prerequisites, then a revision-handling note. No obvious filler. Slightly dense but efficient.

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?

The tool has a complex schema (nested ActionDecision), an output schema (so return values needn't be explained), and annotations covering safety. The description provides the operational requirements (consent, entitlement, idempotency, revision matching) that an agent needs to call correctly. It leaves minor gaps, such as not explaining what happens if the revision is stale.

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%, so the description must compensate. It mentions idempotency_key, confirmation (exact-intent confirmation maps to the confirmed const true), expected_version (approve the exact current revision), and the need to read the action's kind and payload first. While it doesn't spell out every parameter, it meaningfully interprets the schema's intent.

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 (Approve) and a specific resource (the exact current revision of an existing prepared internal action). The tool name and title are mirrored but the description pins down that it operates on a prepared action at a specific revision, which distinguishes it from sibling tools like execute_action, retry_action, and cancel_action.

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?

Gives clear context: approve an existing prepared action; read its kind and payload first; use the current revision when changing an existing record. However, it does not explicitly name the sibling alternatives (e.g. execute_action, cancel_action) or state when not to use this tool.

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