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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, covering the safety profile. The description usefully discloses the return shape (citation, hierarchy heading, snippet, effective date, eCFR URL, total match count), which adds context, but does not disclose pagination behavior or rate limits.

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 tightly-packed sentences, front-loaded with the verb and resource. Every clause earns its place: scope, return fields, and the sibling routing hint. 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?

Given only 2 params at full schema coverage and no output schema, the description covers purpose, result fields, and sibling guidance well. Slight gap: no mention of result ordering, snippet length, or how the total match count can be used (e.g., for pagination), but it is adequate for correct invocation.

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% — both 'query' and 'limit' are documented in the schema with examples and constraints (default 20, max 100). The description adds no syntax or format details beyond what the schema provides, so baseline 3 applies.

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 ('Full-text search') and a precisely scoped resource ('the current Code of Federal Regulations (eCFR, all 50 titles)'). Explicitly distinguishes itself from the sibling reg_cfr_section by naming it and its complementary role (reading full text vs. searching).

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?

Clearly routes agents to reg_cfr_section when they need a full section's text rather than a search result. Does not explicitly state when NOT to use this tool versus reg_search or reg_document, so the guidance is clear but not exhaustive across all regulatory siblings.

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