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

Annotations already cover readOnlyHint, idempotentHint, and destructiveHint, and the phrase “without changing it” aligns with those without adding much. The description does add some context beyond annotations by specifying that the contact is private and project-scoped, but it omits auth/error/not-found behavior. With annotations already handling the safety profile, this is adequate.

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?

A single sentence with no redundant or filler content. Every phrase earns its place: “one” limits scope, “private” adds access context, “selected project” clarifies the lookup scope, and “without changing it” reinforces the non-mutating behavior.

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 simple get-by-id tool, the description combined with the input schema and annotations covers the core invocation: what resource, which project scope, and no side effects. It could be strengthened by naming crm.search_contacts as the discovery alternative and by clarifying the behavior of project_id when null, but the output schema and annotations fill most remaining gaps.

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. It hints at project_id via “selected project” and at the contact identifier via “one private CRM contact”, but it does not explain parameter-level details such as project_id being nullable/defaulted to null. The parameter names and types do some work, but only partial compensation is provided.

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 action (“Retrieve”), a specific resource (“one private CRM contact”), and a scope (“from the selected project”), while also clarifying that the operation does not change anything. This clearly distinguishes it from siblings such as crm.search_contacts and crm.update_contact.

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 gives clear context: this is for fetching a single known contact within a project and is not a mutating operation. However, it does not explicitly name alternatives or state when-not-to-use conditions, so it stops short of full routing guidance.

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