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

With readOnlyHint/openWorldHint/destructiveHint already in annotations, the description adds genuine behavioral detail: the exact shape of the returned path and the note that 'the answer says which date it describes,' which matters for a CFR corpus with versioned dates. It omits any statement about what happens when no identifier is supplied, keeping it from a 5.

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 short, front-loaded sentences with the purpose and return format first and the type/date caveats last. The 'part/subpart/section/appendix accept int or string' clause is efficient compression, though it is slightly dense.

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, the return value needn't be described, and it largely isn't. But for a tool with 6 parameters and zero required ones, the description never says what happens if no identifiers are given, or how title_number=48 interacts with lookups into other titles, leaving a real ambiguity for 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 0%, so the description must compensate and it only partly does: it tells the agent that part/subpart/section/appendix accept int or string, covering 4 of 6 parameters. The 'date' parameter's semantics and the 'title_number' default of 48 are never explained, nor is which combinations of identifiers are valid.

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 first sentence states a specific verb and resource ('Get the breadcrumb hierarchy path') and the second makes the retrieved object concrete ('ancestors from title down to the target node: title > chapter > subchapter > part > subpart > section'). This clearly separates it from sibling tools like get_cfr_content (contents) and get_cfr_structure (overall skeleton).

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 gives a clear use case: 'Useful for understanding where a section sits in the CFR hierarchy and what regulation it belongs to,' which tells the agent when this tool is the right call. It never names an alternative or a when-not condition, so 4 rather than 5.

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