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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the baseline is low; the description still adds real value by disclosing that the data is 'served from the tool layer itself, with no database query' and by listing the exact return fields (tool, source, text, argument_descriptions, sources_available, note). The precedence note about per-response coverage_note is useful governance context. It does not specify size/verbosity of returned text, which would have made it 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?

Front-loaded with the core action, then organized by mode (tool-only, source-code), then returns, then provenance. The long compound sentences pack several clauses each and repeat the schema's example codes, but every sentence carries information.

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 only two parameters and no output schema, the description covers everything an agent needs: both input modes, what each returns, the field list, and where authoritative per-response coverage lives. Nothing required to invoke it correctly 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 coverage is 100%, so 3 is the floor; the description goes slightly beyond by tying the source code to concrete output consequences — 'citation forms, served and held counts and read dates' — and by pairing each tool family with its valid code domain. Much of the example-code content duplicates the schema's own parameter descriptions, limiting the added value.

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 and resource ('Returns GLO's coverage statements as text') and immediately distinguishes itself from the data siblings by being a metadata/coverage lookup rather than a search or fetch. The two operating modes — tool name vs. source code — are named explicitly, so an agent can tell what it will get before opening the 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 clear conditional usage: use a tool name alone for that tool's statement, or pass a source/state code to get regulation-source coverage and citation forms. It stops short of explicit exclusions or a 'do not use when' clause, and the note that data tools' own response notes 'remain the record' implies precedence without stating it as a rule.

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