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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds genuinely new context the annotations lack: an authentication requirement and the semantic content of the result (including that 'incomplete outcome evidence' is surfaced).

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?

A single front-loaded sentence with the resource stated first, then the breakdown dimensions, then the auth note. Dense but no filler; a slight cost is that the em-dash list of labels is a bit terse.

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 one-parameter read-only stat tool with no output schema, the description usefully names the return dimensions and the auth prerequisite. Complete enough for an agent to invoke correctly; only the lack of sibling routing is a minor 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% and the sole parameter (campaign_id) already documents that it is a Campaign UUID sourced from list_outreach_campaigns. The description adds nothing beyond the schema, so the baseline 3 for full coverage 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 resource and scope ('Pipeline-stage breakdown for one outreach campaign') and enumerates the exact fields returned (total/sent/active/won/lost, ratio, incomplete evidence). It is clearly distinguishable from a create/list tool, though it does not explicitly differentiate itself from the nearby outreach_analytics sibling.

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?

The description implies usage by specifying it is scoped to a single campaign's pipeline stages, but it never states when to prefer this over outreach_analytics or the list_* siblings, nor any exclusions. Usage is inferable rather than stated.

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