Get Contact by ID

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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description contributes one useful behavioral fact—that the response aggregates contact persons alongside the contact. It says nothing about not-found behavior, permissions, or response shape, so it adds only modest value.

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 and free of filler. The first sentence is a verbatim restatement of the title, which is slightly redundant, but the second earns its place by disclosing the aggregated contact persons.

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 single-parameter read tool with full annotations, the definition is adequate but minimal. It omits error behavior for an invalid or unknown ID, and does not clarify what contact persons are or how many might be returned—reasonable gaps given no output schema exists, but still 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 coverage is 100%; contactId is fully documented with type, UUID format, and pattern. The description adds no meaning beyond the schema, 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?

The description names a specific verb and resource ("Retrieves a single contact") and adds a genuine detail beyond the name: the response includes associated contact persons. It never distinguishes itself from siblings like get_contact_by_email or search_contacts, so it stops short of a 5.

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?

There is no when-to-use guidance and no mention of alternatives, despite three closely competing siblings (get_contact_by_email, search_contacts, list_contacts). The phrase "by ID" weakly implies the caller must already have an ID, but that inference is left entirely to the agent.

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