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

With no annotations, the description carries the burden and it discloses an important behavioral trait: the pause is reversible and launch_campaign resumes it. It also clarifies that the operation affects every channel. It doesn't mention idempotency or in-flight sends, but for this simple operation the key behavior is covered.

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?

Two concise sentences with no filler. The action and scope are front-loaded, and the second sentence provides a useful recovery path. Every sentence earns its place.

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 operation with no output schema, the description covers the action, scope, target state, and reversal path. The required id is visible in the schema, so no return-format description is needed. Minor edge cases like idempotency are omitted but nothing essential to invoking the tool is missing.

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?

The schema has one required string id with 0% description coverage, so the description must supply meaning. The phrase 'a campaign' implies id identifies the campaign to pause, but the description never explicitly ties id to the campaign or adds details. Since the single parameter is self-evident, this is adequate but not additive.

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 names a specific verb ('Pause'), resource ('campaign'), and scope ('across every channel'), clearly identifying what the tool does. The 'running' condition and the contrast with the sibling pause_channel make the purpose unambiguous.

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?

It states the condition for use ('a running campaign') and the all-channel scope, which implies pause_channel is the alternative for one channel. It also names launch_campaign as the resume action, giving the agent an explicit next step. It does not spell out exclusions such as already-paused campaigns, but the context is clear.

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