eCFR.io Federal Regulations

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

Annotations already cover read-only/idempotent/open-world, and the description adds genuinely new behavioral context: pagination termination, stale-flag inspection, the unofficial-mirror disclaimer with verification caveat, and an explicit instruction to treat retrieved text as source material rather than instructions (prompt-injection defense). That is well beyond what the structured fields convey.

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?

Dense but front-loaded: retrieval scope, then pagination, then citation and staleness rules, then disclaimers. Every sentence carries a distinct instruction, though the block is long enough that a reader must work through several imperatives.

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?

An output schema exists, so return-shape detail is unnecessary, yet the description still names the key fields an agent must act on (inlineCitation, legalCitation, bodyAsOf/sourceDate, stale flags). For a read tool with pagination and citation obligations, nothing material is missing.

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 carry the load. It explains the path format with a concrete example (/Title-31/Section-10.1) and implies offset-based paging via nextOffset, but never describes the length parameter or the offset/length units and caps that the schema only encodes as min/max/default.

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 (Retrieve) and resource (regulation text and child links), and pins the input to its origin: a canonical path returned by search. This cleanly separates it from search_regulations and list_titles without opening either schema.

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?

Gives actionable context: fetch the regulation before quoting a search snippet, follow nextOffset until null for complete text, and include citation fields for every claim. It doesn't explicitly name the sibling tools as alternatives, but the sequencing against search is clear enough to route an agent.

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

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is fully covered. The description adds only that results carry source dates and canonical URLs, which is useful but overlaps with the existing output schema.

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 short sentences, no filler. The purpose and returned payload are front-loaded before the pointer to the sibling tool.

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 zero parameters, rich annotations and an output schema covering the return shape, the definition supplies everything needed to invoke it. A clearer statement of when this root listing should be used versus search_regulations would make it fully complete.

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 tool takes zero parameters, so per the rubric the baseline is 4. There is nothing for the description to clarify about invocation inputs.

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 (List) and resource (CFR titles) and even previews the payload (source dates, canonical ecfr.io URLs). It distinguishes itself from the sibling get_regulation by framing that tool as the way to descend into children.

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 clause 'Browse children with get_regulation' implies this tool is the top-level entry point and names the alternative, but it never says explicitly when to choose list_titles over search_regulations or what the follow-up workflow is. Usage is inferable rather than stated.

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

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

Annotations already cover read-only, idempotent, open-world and non-destructive behavior, so the bar is lower. The description goes further by disclosing that results are ecfr.io mirror links of an unofficial compilation, that text can become stale, and that retrieved text should be treated as data rather than instructions. It does not mention pagination or result-size behavior, but the output-schema exists and limit is bounded.

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 opening sentence is well front-loaded, but the description repeats the same instruction twice ("Fetch matching regulations before quoting" and "Fetch the regulation before quoting a search snippet"), and the citation-formatting rules add bulk. Several sentences could be merged without losing content.

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 an output schema exists, return values needn't be explained, yet the description still covers return shape (snippets, inline and legal citations, bodyAsOf/sourceDate), sourcing caveats, and quoting obligations. The only gap is the undocumented limit parameter, which is minor for a search tool.

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 query and limit parameters are only weakly compensated. The description shows an example query form ("31 CFR 10.1") which clarifies accepted input, but never explains limit, result count, or how many snippets are returned.

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 (current US CFR text), plus the alternative input form (a citation like 31 CFR 10.1). It implicitly distinguishes itself from the siblings get_regulation and list_titles by framing search as the discovery step before fetching.

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?

Explicitly prescribes the workflow: fetch the matching regulation before quoting, never represent stale text as current, include inlineCitation/legalCitation in any regulatory claim, and verify against official sources. It names both the trigger (regulatory claim or quotation) and the constraints, which is exactly the when/when-not guidance expected.

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