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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the description is not required to restate that. It still adds non-obvious behavior: results are grouped by rule_stage, the edition defaults to the newest actually loaded, and the agency match also covers the parent agency's sub-agency rules. Missing is any note on truncation/pagination behavior beyond the schema's limit.

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 sentences and a parenthetical: scope first, then the routing alternative. Zero filler, and the most decision-relevant information (what it returns and when not to use it) is front-loaded.

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 no output schema, the description compensates by stating what comes back (every open RIN, grouped by rule_stage) and that it can answer count-style questions per stage. Combined with the 100%-covered schema and safety annotations, an agent has everything needed to select and call 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?

Schema description coverage is 100%, so all three parameters (agency matching semantics, edition YYYYMM default, limit range) are already fully documented in the schema. The description only echoes the "given or newest edition" default and adds no new parameter-level syntax or format guidance. 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?

The description states a specific verb+resource with scope: one agency's full regulatory agenda for a given or newest edition, returning every open RIN grouped by rule_stage. It explicitly names the sibling tool it is not (reg_agenda_search), so an agent can distinguish them without opening a 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?

It gives concrete when-to-use framing via example questions ("what is EPA's regulatory agenda", "how many rules does DOL have in the proposed stage") and states the exclusion condition: use reg_agenda_search when filtering by keyword or across agencies. When/when-not/alternative are all present.

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