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

readOnlyHint=true already tells the agent this is a safe, non-mutating read, and 'GET /entity' merely restates that. The description adds that matching is by name/email/foreignId, but says nothing about cursor-based pagination behavior, default page size effects, or result ordering — modest added value over what annotations and schema already convey.

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?

Two tightly packed sentences: the capability and entity taxonomy come first, the usage guidance second, with zero filler. Nothing could be cut without losing routing or lookup 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?

For a 10-parameter, all-optional, read-only search tool with no output schema, the description gives enough to select and shape a call; the rich schema carries the filtering and pagination detail. Only the lack of any note on pagination/result-window expectations keeps it from a 5.

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%, so all 10 parameters are already self-documented with limits, defaults and examples. The description's mention of name/email/foreignId search fields overlaps with the 'search' and 'foreignId' schema descriptions rather than extending them, making the baseline 3 appropriate.

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+resource ('Find/search entities') and enumerates the entity subtypes (buyers, vendors, payors, payees) plus the searchable fields, and names the HTTP endpoint. It is clearly distinguishable from create_entity and get_entity in intent, though it never explicitly contrasts itself with get_entity for single-ID retrieval, leaving full sibling disambiguation to inference.

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?

'Use to look up counterparties by name/email/foreignId or list all' gives explicit usage context and the two primary modes (search vs. list-all). There are no when-not conditions and the retrieval sibling (get_entity) is not named as an alternative, so it falls short of a 5.

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