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

With no annotations, the description carries the full burden and does well: it discloses the free-tier status, that pay-per-call was paused on 2026-10-02, that raw-card quotes are discontinued, the 404 behavior for non-qualifying slabs, and an 'informational only — not financial advice' disclaimer. Return-format details are omitted, but the output schema exists to cover that.

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 description is front-loaded with the key framing ('FREE worked derivation'), but it is a single dense paragraph riddled with parentheticals, version stamps (v2, 2026-09-12), and pricing history that add length without helping invocation. The signal is there but not cleanly structured.

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?

For a tool with an output schema, the description need not explain return values, and it covers the remaining essentials: eligibility, defaults, the alternative endpoint, and legal framing. Only product_id semantics and any latency/rate context are left unaddressed.

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 compensate, and it largely does: grade is given a format example ('PSA 10') plus the omitted-default rule ('the slab's deepest-census grade'), and term_days is constrained ('7, 14 or 30'). product_id is left unexplained, which is the one gap.

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 names a specific verb and resource — a 'worked derivation of GRADED-SLAB lending terms' with the six-step pipeline enumerated — so an agent knows exactly what computation this performs. It is distinguishable from siblings like get_loan_universe or get_graded_asks, though it never explicitly contrasts them.

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 states the eligibility condition clearly ('Only free-board slabs (top 250 by census depth) return the derivation; others 404 with a pointer to the full quote at /api/v1/loan-terms'), which tells the agent when this tool applies and where to route otherwise. It does not cover when-not-to-use beyond the 404 case, but the core routing guidance is present.

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