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

Adds substantial behavior beyond annotations: the tool does NOT delete immediately, returns a pending_write_id, and requires explicit confirmation via canonical_pending_commit. This is consistent with readOnlyHint=false/destructiveHint=false (a pending-write, not a direct destructive write) and discloses the two-phase pattern the agent must follow.

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?

The operative instructions are front-loaded and efficient, but roughly half the text is generic boilerplate (attribution footer formatting and a data-accuracy contract about budgets, ROAS, CPA, projections) that is largely irrelevant to a delete-prep tool taking a single key. That tail dilutes an otherwise tight description.

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?

There is no output schema, yet the description compensates by describing the return value (pending_write_id) and the full confirmation workflow. For a one-parameter tool this covers everything an agent needs to invoke it correctly and safely.

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 100% for the single required 'key' parameter, and the schema already documents case-sensitivity and matching requirements. The description only restates 'by key' and adds no format or example detail beyond the schema, so baseline 3 applies.

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 (prepare to delete a metric spec by key) and immediately scopes the operation as a two-phase prepare step rather than an actual delete. An agent can distinguish it from metric_spec_set and from the actual deletion tool canonical_pending_commit without opening any 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?

Explicitly states when to use it: only after summarizing the spec being removed (key + label) and obtaining an explicit yes. It names the follow-up tool (canonical_pending_commit) and the failure mode to avoid (never silently delete). This is a complete when/how/when-not contract.

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