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

Annotations already declare readOnlyHint=true, so the safe-read profile is covered structurally. The description adds the backing endpoint (GET /contacts/{contact_id}), which is useful context, but says nothing about not-found behavior, auth requirements, or what a miss returns.

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 short sentences, front-loaded with the core action (get one contact) followed by the API mapping. Nothing is redundant or padded.

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?

A simple single-record read whose annotations carry the safety profile and whose schema fully documents inputs, so it is mostly adequate. However, with no output schema, the description gives no hint about the returned contact shape or how 'fields' affects the response.

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% and both parameters are documented in the schema, including the 'fields' selection parameter. The description adds no syntax, format, or examples beyond that, so the baseline 3 applies.

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 with scope: 'Get a single contact by id.' The word 'single' implicitly distinguishes it from keap_list_contacts and keap_get_company, but the sibling is not named explicitly, so it stops short of the top score.

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 phrase 'by id' implies the precondition (you need a contact_id) and the single-record use case, but there is no explicit when-to-use guidance, no mention of keap_list_contacts as the alternative for lookups without an id, and no exclusion cases.

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