Apply a Meta (ads, pixel, catalog, Instagram, Page) plan

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

The annotations already declare destructiveHint=true, idempotentHint=false and openWorldHint=true, and the description adds real execution semantics beyond that: locks are re-checked, operations run in order, execution halts at the first error, and everything is journaled. That failure-mode and sequencing detail is exactly the context an agent needs before invoking a destructive write.

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 the 'WRITE' classification and the action, then the required inputs, then the execution behavior. No filler and no repetition of schema fields.

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 the workflow position, the input contract and the failure/journaling behavior. It stops short of describing what is returned after a run (e.g. a journal/audit reference the caller would use to verify results), which is the one remaining gap.

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 the baseline is 3, but the description adds a meaningful constraint the schema does not: plan_id, confirmation_token and confirm must be passed exactly as returned by the plan_* tool, i.e. unchanged and not reconstructed. That is a substantive hint about value provenance.

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 ('apply') on a specific resource ('a signed plan for Meta'), and the 'WRITE' prefix plus the platform scoping (ads, pixel, catalog, Instagram, Page) distinguishes it from the read-oriented Meta siblings (meta_campaigns, meta_insights) and from the meta_plan_* generators. An agent can identify it as the execution step of the plan workflow without opening the 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 a clear precondition ('after the user approved it') and references the plan_* tools as the source of the required values, which tells the agent this must follow a plan/approval step rather than be called directly. It does not explicitly name rollback_plan or state when NOT to use it, so it stops short of full alternative routing.

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