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

Annotations declare destructiveHint=true and idempotentHint=false, and the description adds context beyond them: irreversibility (cannot be resumed, sent messages stay sent), allowance release, the module-enablement requirement, and a prescribed error-recovery path via fetch_messaging_usage. This is materially more than the structured fields provide.

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?

Front-loaded with the irreversible warning and confirm requirement, and the alternative-routing advice follows. Long, but nearly every clause carries a distinct operational instruction; a small amount of the error-handling tail could be compressed.

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 destructive, non-idempotent mutation with no output schema, the description covers irreversibility, confirmation protocol, prerequisites, alternative tooling, and error recovery — nothing an agent needs to call it safely is missing.

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 coverage is 100%, so baseline is 3, but the description adds genuine semantic weight to 'confirm' — it must be set only after explicit in-conversation approval of this specific action, never carried over or used to satisfy the schema. That is behavioral meaning the schema's own text does not fully duplicate.

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 precise verb+resource plus scope restriction ('a campaign that has not finished') and the side effect ('release the monthly allowance it was holding'). It explicitly distinguishes itself from pause_campaign and resume_campaign, so an agent can route correctly without opening a schema.

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 when-to-use (unfinished campaign), when-not (offer pause_campaign first if the user only wants to stop temporarily), a hard precondition (confirm=true required), and failure handling ('on 403 module not enabled, do NOT retry' and 'call fetch_messaging_usage first' when a send is refused). Exclusions and alternatives are explicit.

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