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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description still adds meaningful behavioral context beyond that: it enumerates the returned artifact (cells, effective dates, issuer document, required qualifiers, what the table does not establish, sha256), which is valuable since no output schema exists.

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 ANSWSERS/PARAM/NOT FOR labeling front-loads the useful content and the whole thing is compact. The test-result sentence (3/25 without the file vs 25/25 with it) is slightly promotional, but it is a single clause and arguably earns its place as justification for invoking the 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 no output schema and only one optional parameter, the description covers what an agent needs: what questions it answers, how to source the id, what the payload contains, and the temporal/index boundary. The only gap is not naming a sibling when routing away from this 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 100% and the schema already documents rule_id and the omit-to-list behavior, so the baseline is 3. The description adds value by stating the id comes "from the index" and by confirming the omit case lists every published rule, clarifying where the identifier is discovered rather than just its format.

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 gives a specific resource (dated regulatory rule table) and concrete question examples ("what is the current FHA loan limit", "which FHA MIP table is in force") that make the tool's purpose unmistakable. It does not, however, distinguish itself from closely related siblings such as resolve_fha_annual_mip, which reads as overlapping with the MIP-table example.

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?

Usage is framed by four representative questions plus an explicit "NOT FOR" clause excluding rules absent from the index and anything predating the effective date. This is clear when/when-not guidance, but it stops short of pointing to a sibling alternative for the excluded cases or for the overlapping MIP-resolution case.

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