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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so safety is well covered. The description adds meaningful context beyond that: the returned capability flags, the note that odds are information only and not betting advice, and the credential distinction relative to list_orgs.

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?

One dense sentence front-loads the action, resource, and parameter, then lists the output fields and the key caveat. No filler or redundant phrasing is present.

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, read-only tool with rich annotations and no output schema, the description covers the return fields, the capability flags, the odds caveat, and the relationship to list_orgs. Nothing an agent needs to invoke it correctly 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 fully documents the single parameter with an enum and 'Promotion slug' as its description, so coverage is 100%. The description repeats the enum values but does not add semantic meaning beyond what the schema already provides, which matches the baseline of 3.

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 opens with a specific verb and resource: 'Fetch one promotion by slug,' and enumerates the exact fields returned. It also names the sibling list_orgs for contrast, making the tool's purpose easy to distinguish.

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 explicitly references list_orgs and notes that it returns the same rows for every promotion without a credential, giving useful context about when the broader endpoint might be appropriate. It stops short of an explicit 'use X when / use Y when' rule, but the guidance is clear enough.

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