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

readOnlyHint=true already tells the agent this is a safe read; the description adds the underlying endpoint (GET /crm_persons/{id}) and the scope token, which help an agent map the call to the CRM entity. It says nothing about behavior on a missing/invalid id (404 vs empty result) or what is returned.

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 short fragments, front-loaded with the action, no filler. 'Scope: crm_person' is mildly redundant with the resource already named in the first sentence.

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 one-parameter read tool with readOnlyHint is nearly self-explanatory, but with no output schema the description never indicates what a contact record contains or what happens when the id does not resolve.

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 the single contact_id is fully documented as a numeric string id, so the schema carries the load. The description's 'by id' adds nothing beyond it – baseline 3.

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?

Specific verb+resource: 'Get one contact person by id', which is clearly a single-record fetch and distinguishable from list_contacts. It does not, however, differentiate itself from traffit_get_client, which an agent could plausibly confuse with a contact lookup.

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?

'by id' implies the tool is for when a known identifier is in hand, versus the list_contacts sibling for discovery, but this is left implicit. No when-not-to-use or prerequisite guidance is given.

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