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

Annotations already cover readOnly/idempotent/non-destructive, so the bar is lower, yet the description adds real behavioral context: sources and last-checked date are returned, and retired ids yield a retirement date plus the replacement requirement. That edge-case behavior is not visible in the annotations or input schema, though nothing beyond that is disclosed.

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 tight sentences, front-loaded with the core action and followed by the edge case. No filler.

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?

With an output schema present, return shape need not be described, and the description still covers the primary path and the retired-id path. The only minor gap is the not-found case, which is not addressed but is partially implied by the retired-id handling.

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?

Schema coverage is 100% with the id parameter documented, so the baseline would be 3. The description goes beyond the schema by giving a concrete id format example (claude.rule-annotations), which helps the agent construct a valid value.

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 ("Returns one requirement by its id") with a concrete example id, making it clearly distinct from the list/search siblings like search_requirements and get_platform_requirements. It even scopes the edge case of a single-item lookup vs. bulk retrieval.

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 phrase "by its id" implies the precondition (you must already know the id), which is the natural dividing line against search_requirements, but it never states that explicitly or names the alternative. Usage is inferable rather than spelled out.

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