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

Annotations already declare destructiveHint=true, openWorldHint=true, and non-idempotency, so the safety profile is covered. The description adds real hidden behavior beyond that: a safety cap blocking budget increases above +50%, and confirm=false acting as a preview/dry-run. It stops short of covering permissions, reversibility, or which downstream entities are affected.

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?

Four dense fragments, front-loading the core action and then the two highest-risk parameter semantics (status enum, budget cap). No filler sentences; every clause carries operational information.

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 no explanation, and the description covers the mutation's key behavioral constraints. Only minor gaps remain around the undocumented name parameter and any note on how changes can be inspected or reversed.

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 0%, so the description must compensate, and it meaningfully does: it enumerates valid status values, states that daily_budget uses the main unit, and defines the confirm preview flag. The name, account_id, and campaign_id parameters remain undocumented, leaving a small gap.

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 and resource ('Updates a Meta campaign') and clarifies the partial-update scope with 'only the provided fields'. It does not explicitly distinguish itself from close siblings like update_campaign or pause_campaign, though the status note hints at the relationship.

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?

Offers implicit routing ('use PAUSED to pause') and partial-update semantics, but never states when this tool should be chosen over update_campaign, update_campaign_status, or pause_campaign. Usage is implied rather than spelled out.

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