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

Annotations only supply a blunt destructiveHint=true; the description usefully refines this by clarifying that it is a partial update (only included fields change) and that Auto Increment / Formula / Equation fields are read-only, plus it states the return ('the updated record'). It stops short of covering permissions, rate limits, or error behavior for nonexistent records.

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-loads the critical fact ('MUTATES Knack data') in the first clause and keeps the four sentences tight. The read-only field warning and the `fields` keying example are each stated twice (description and schema), which is 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?

With no output schema, the description correctly states that the updated record is returned, and it covers the mutation semantics and write-restricted field types. It omits what happens on invalid record ids or partial failures, which would matter for a destructive PUT.

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 all three parameters are documented in the schema with examples, so the baseline is 3. The description's example of `fields` keying largely repeats the schema's own example and the read-only warning, adding little beyond structured data.

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 and resource ('updates a record' on Knack data) and even names the underlying API call (PUT /objects/{object_key}/records/{record_id}), which cleanly separates it from knack_create_record, knack_delete_record and knack_get_record. An agent can identify the operation without opening the schema.

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?

The description implies usage by explaining that only included fields change, which is useful partial-update guidance, but it never says when to prefer this over siblings such as knack_request or how it differs from a full replace. No exclusions or alternatives are named, so the agent must infer the routing.

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