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

Adds important context beyond annotations: it enumerates returned data, confirms read-only behavior, clarifies that this call is NOT gated by the Send Message module unlike writes, and explains 403 semantics. No contradiction with readOnlyHint=true or destructiveHint=false.

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 sentences, each serving a distinct purpose; the core purpose and the critical usage rule for pause/resume/cancel are front-loaded. No filler.

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 single-resource read with no output schema, the description fully covers return shape (content, audience, sender profile, counters, actions), downstream usage, and error handling. Annotations cover safety, so the remaining context is sufficient.

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?

There is one parameter with 100% schema description coverage; the schema already defines campaign_token as a UUID v4. The description does not add parameter-level meaning beyond referring to 'one campaign' and 'this call', so the baseline of 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?

States a specific verb ('Fetch') and resource ('one campaign in full'), enumerates returned components (content, audience, sender profile, counters, actions), and distinguishes from siblings like fetch_campaigns by singular scope and from pause/resume/cancel by read-only status.

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 tells the agent to read the action list before offering pause, resume, or cancel, tying invocation to a downstream workflow; also gives a 403 diagnostic rule ('look for another cause before telling the user the module is off'). This names alternatives and conditions clearly.

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