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

Annotations already declare readOnly/idempotent/non-open-world, and the description reinforces this with 'Static reference with no network access,' plus adds value the annotations cannot: an as-of date, sourcing per code, and an 'informational, not legal advice' disclaimer. It does not, however, describe output shape or size 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?

Front-loaded with the core action and the return contents, then the input modes, then the safety disclaimer. Dense but nearly every clause earns its place; only the parenthetical examples add mild redundancy.

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?

No output schema exists, so the description compensates by enumerating exactly what each result contains (label, meaning, who counts, cautions, source, as-of date). Combined with the input modes and the static/no-network note, an agent has everything needed to call and interpret it.

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?

With 0% schema description coverage the description carries the burden, and it does: 'codes' are numeric eligibility codes (examples 23, 12, 99), 'applicant_types' are named categories (example small_business), and passing neither yields the full 17-code table. It stops short of explaining how codes and applicant_types combine when both are supplied.

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 (decode/explain) and resource (Grants.gov applicant eligibility codes) and immediately distinguishes itself from the sibling search/retrieval tools (get_grant, search_grants, grants_closing_soon) by being a static code-to-meaning reference. Examples (23, 12, 99) make the subject unambiguous.

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 tells the agent what to pass: 'Give codes, applicant types ... or nothing for the full table of 17 codes,' which covers the three input modes. It lacks an explicit when-not / alternative-tool statement, but the context is clear enough for correct invocation.

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