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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context: ordering ('newest first'), the fields returned, and the authentication requirement. It does not mention pagination beyond the limit parameter, but the schema covers that.

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 description is a single, front-loaded sentence that conveys the core purpose, ordering, and return fields without waste. The authentication note is a useful addition and does not bloat the text.

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 read-only list tool with full schema coverage and safety annotations, the description is nearly complete. It covers what is returned, ordering, and authentication. It does not describe the output format, but there is no output schema and the tool is simple enough that an agent can infer the return shape from the listed fields.

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%, so the schema already documents all three parameters. The description adds a bit of context by mentioning 'reply classification' and 'newest first', which relates to the direction parameter's meaning, but it does not add significant meaning beyond the schema. Baseline 3 is appropriate.

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?

The description states a specific verb ('List'), a clear resource ('sent / received emails for an outreach campaign'), and adds ordering ('newest first') plus included fields ('subject, body preview, and reply classification'). This clearly distinguishes it from sibling tools like list_outreach_campaigns or outreach_analytics.

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 context: it is for retrieving campaign email activity, and the schema's campaign_id reference to list_outreach_campaigns provides a prerequisite. It does not explicitly state when not to use it or name alternatives, but the context is clear enough for an agent to select it appropriately.

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