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

Annotations already declare readOnlyHint=true, and the description adds the HTTP GET method, which is consistent but minimal. It does not disclose pagination, rate limits, or response structure, though these are less critical for a zero-parameter read-only list operation.

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 two short sentences with no redundant wording. The core behavior is front-loaded, and the API endpoint provides useful technical context without sacrificing brevity.

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 zero-parameter, read-only list tool, the description is complete. It identifies the resource, the scope (workspace), and the underlying API call. No additional context seems necessary for an agent to invoke this tool correctly.

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 tool has no parameters, so parameter semantics are not applicable. The description correctly explains the operation without needing to add parameter-specific detail, and the schema coverage is complete by virtue of being empty.

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 uses a specific verb and resource: 'List all campaigns in the workspace.' This clearly distinguishes the tool from siblings like customerio_get_campaign, which retrieves a single campaign. The API endpoint reinforces the exact scope without ambiguity.

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 clearly states the tool's purpose: listing all campaigns in the workspace. It does not explicitly name alternatives or exclusions, but the 'all campaigns' framing makes the use case evident and distinct from single-entity or metric-focused tools.

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