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

Annotations already declare readOnlyHint=true, and the description adds genuinely useful context with the required scope read:rate, which an agent cannot get from structured fields. However, it says nothing about whether results are paginated, scoped to a date range, or active/inactive, which matters for a list endpoint with no output schema.

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 short sentences, purpose first and the auth requirement second, with zero filler. Every sentence carries information the agent needs.

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-param, read-only listing with readOnlyHint annotations, the description covers what it does and what credential scope is needed. The only notable gap is return behavior (pagination, whether inactive promotions are included), which is more than the minimum but short of complete for a tool with no output schema.

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 takes zero parameters, so the baseline is 4; there is nothing to document and the description correctly doesn't invent parameters. The scope note is an auth concern rather than a parameter, so it does not detract.

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?

States a specific verb and resource ('List the promotions configured for the property'), which cleanly separates it from siblings like list_rate_types and list_blackouts. It doesn't explicitly name those siblings, but the resource noun alone is distinctive enough.

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?

Usage is implied by the resource name rather than stated; there is no guidance on when to prefer this over list_rate_types (promotions vs rate types are easily confused) or any prerequisite context. For a zero-param list tool this is minimally viable but leaves a real ambiguity unresolved.

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