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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered structurally. The description adds real behavioral value by disclosing that the payload includes do-not-contact status and how much conversation history exists in each direction, but says nothing about permissions, pagination, or empty-result behavior.

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, front-loaded sentence with no filler, and the enumeration is genuinely informative rather than padding. It is slightly list-heavy for one sentence, but every clause earns its place by naming a returned field.

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 and only one well-documented input, the description carries the burden of explaining the return payload and does so by enumerating the categories of data returned. Coverage is good for a simple read tool; only edge cases such as a nonexistent or inaccessible contact_id are left unaddressed.

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?

There is a single parameter and schema description coverage is 100% — the schema already explains contact_id and even points to search_contacts as the source. The description adds no format, range, or lookup guidance beyond that, so the baseline of 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 gives a specific verb+resource ("Show one contact") and enumerates exactly what is returned: profile details, campaign, status, outreach state, do-not-contact status, and per-direction conversation history. The singular "one contact" implicitly separates it from the list-style sibling search_contacts, but no sibling is named explicitly, so it stops short of full differentiation.

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?

Usage is only implied: an agent can infer this is the single-record lookup that follows search_contacts (which the schema also references as the id source). There is no explicit when-to-use statement, no condition that selects it over search_contacts or get_conversation, and no exclusions.

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