Read latest campaign results

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

No annotations are provided, so the description carries full burden. It discloses that the tool returns only the latest aggregate and not historical snapshots, which is key behavioral transparency. It does not mention side effects, permissions, or rate limits, but for a simple read tool this is acceptable.

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 sentences: first states the main action, second provides important context. No wasted words. Front-loaded with the purpose.

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 simple tool with one parameter and no output schema, the description is complete: it explains what it fetches, the data limitation, and the alternative. It does not describe return format, but since no output schema exists, this is acceptable.

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?

Only one parameter 'id' with schema description 'Campaign UUID.' The description adds no additional meaning beyond the schema. Since schema coverage is 100%, baseline is 3. No improvement needed.

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?

Clearly states 'Fetch the latest results snapshot for a campaign.' The verb 'fetch' and resource 'latest results snapshot' are specific. It distinguishes from sibling tools like campaign_get by implying this returns performance data. However, it does not explicitly list the aggregate fields (impressions, clicks, conversions) in the description, relying on the title 'campaign_results' to imply that.

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?

Provides explicit context: 'v1 only stores the latest aggregate... time-series snapshots land with the destinations framework.' This tells the agent when to use this tool (for latest aggregate) and when to use alternatives (destinations for time-series). No other sibling tools need this level of guidance.

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