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

The readOnlyHint annotation already signals a safe read operation. The description adds useful behavioral detail: exact matching, inclusion of lettered subrules (e.g., 601.2a-i), and that it returns the full context. This goes beyond the annotation without contradicting it.

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 is two sentences, front-loaded with the verb and resource, and includes an illustrative example. No redundant or repetitive wording.

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 single-parameter read tool with an output schema and strong annotations, the description covers purpose, usage context, parameter semantics, and behavior fully. It is clear enough for an agent to select and invoke it correctly.

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 input schema has no description for the 'ref' property, so the description carries the burden. It does so well by specifying the exact rule number format and giving an example. However, it could have been slightly more explicit about accepted formats (e.g., whether subrule references are also accepted).

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 clearly states the tool fetches a Comprehensive Rules entry and its lettered subrules by exact number, with a concrete example. This distinguishes it from search_rules and other siblings by emphasizing exact-number lookup and full-context 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?

It explicitly says 'Use after search_rules to read a rule's full context,' providing a clear workflow context and an alternative tool. It does not enumerate exclusive when-not cases, but the sequential guidance is enough for typical use.

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