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

Annotations already mark the tool as readOnlyHint=true. The description adds value by detailing the returned fields and confirming the HTTP GET method and endpoint. It does not contradict annotations. However, it omits potential error conditions or rate limits, which would be useful for completeness.

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 consists of two concise sentences. The first states the primary action and parameter, the second details the return value. It also includes the API endpoint for reference. No extraneous information.

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?

Given the simplicity of the tool (single parameter, no output schema), the description adequately explains what the tool does and what it returns. It could briefly note that the campaign_id is required, but the schema already specifies this.

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 covers 100% of the single parameter (campaign_id) with a description. The tool description adds minimal extra meaning beyond stating 'by its id'. Baseline 3 is appropriate given the high schema coverage and simple parameter.

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 explicitly states 'Get a single campaign by its id' and lists the returned fields (name, status, subject, from, content, created_at). This clearly identifies the action, resource, and scope, distinguishing it from sibling tools like listing campaigns or getting reports.

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 when retrieving a campaign's full state, but it does not explicitly state when to use this tool versus alternatives like emailoctopus_get_campaign_report or emailoctopus_list_campaigns. No exclusions or when-not-to-use guidance is provided.

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