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

Annotations already declare non-read-only, non-destructive, non-idempotent, closed-world, so the safety burden is partly carried. The description still adds genuine behavior: the rename works regardless of campaign status and no other field is touched, which is exactly the reassurance an agent needs for a mutation tool.

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 clauses, zero filler, with the action and the unchanged-scope guarantee front-loaded. Nothing here could be cut 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?

No output schema exists, but for a trivial single-field mutation with annotations covering the safety profile, the description is nearly sufficient. It leaves the confirm/hard-to-undo interaction to the schema's own description rather than surfacing it, which is the only real omission.

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 67% (campaign_id and confirm are documented, name is not). The description adds nothing about parameter format or the confirm guard and only obliquely informs campaign_id semantics via "(any status)", so it neither compensates for the gap nor goes beyond the schema.

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+resource ("Rename a campaign") and constrains scope with "(any status)". The clause "Nothing else changes" implicitly separates it from update_campaign_settings/update_campaign_sequence, but it never names those siblings explicitly.

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?

"(any status)" gives a real usability condition — the campaign need not be paused/draft — which is useful given launch_campaign/pause_campaign/resume_campaign siblings. However, no alternative is named and no prerequisite (e.g., permissions, confirm flow) is stated, so guidance is only implied.

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