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

Annotations already declare readOnly/non-destructive, but the description goes well beyond them: it discloses that no sign-in is required, that signed-out or below-Professional callers receive a degraded payload (`name` and `module` only), and that the `risk_band` filter is actively refused at that tier. These are non-obvious behavioral constraints an agent cannot get from the schema or annotations.

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?

Three tight sentences: capability first, then return fields, then access constraints. Every sentence carries distinct information and nothing is padded or restated from the schema.

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?

There is no output schema, so the description correctly compensates by naming the headline fields returned per match. Combined with the access-tier and filter-refusal disclosures, an agent has enough to call this correctly and interpret the response, including the degraded case.

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 the baseline is 3, but the description adds meaning the schema does not carry — specifically that the `risk_band` parameter is rejected for unauthenticated/free-tier callers, and that match records expose `score`, `risk_band`, and `subtype` as headline fields. That is genuine parameter-level nuance beyond the field descriptions.

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 and resource ("Search ACI providers") and enumerates the filter dimensions (free text, module, risk band, subtype). It is clearly distinguishable in kind from siblings like get_provider_detail or compare_providers, though it never names an alternative to route between 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?

Usage is implied rather than stated: the agent can infer this is the discovery/list endpoint, but there is no explicit "use this when X, use compare_providers when Y" guidance. The access-tier notes describe behavior, not when to select this tool over its siblings.

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