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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false, so the safety and side-effect profile is fully covered by structured data. The description adds the return-field inventory (number, title, type, agency, abstract, URL), which is useful, but does not disclose pagination behavior, rate limits, or how 'matching' is performed (full-text vs. metadata). With annotations carrying the behavioral load, a 3 is appropriate.

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?

Three sentences, front-loaded with purpose, then return shape, then the routing alternative. No filler, no repetition of schema details, and the most decision-relevant information (what it searches, what it returns, where to go next) is in the right order.

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 read-only search tool with 100% schema coverage and no output schema, the description covers purpose, scope, return fields, and sibling routing – nearly everything an agent needs. The only gap is that with no output schema, the description could clarify result ordering or pagination behavior, but the enumerated fields largely satisfy the return-value burden.

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 description coverage is 100% – every parameter including term, type, limit, agency, published_from, and published_to has an inline description with examples and formats. The description adds only a high-level summary of the filter set (keyword, agency, document type, date), which largely restates what the schema already documents. Baseline 3 is correct.

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 (Search) and resource (Federal Register), enumerates the document categories covered (rules, proposed rules, notices, presidential documents), and names the available filter dimensions. It explicitly distinguishes itself from the sibling reg_document by defining itself as the search entry point vs. the full-text retrieval tool.

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 final sentence performs explicit routing: 'Use reg_document to get the full text of one document.' Combined with the fact that all parameters are optional (keyword-only discovery is possible), the description makes the when-to-use contract clear and names the natural alternative.

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