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

Annotations already declare readOnly, idempotent, non-destructive and closed-world behavior, so the safety profile is covered. The description adds the returned field set, which is genuine value given there is no output schema, but says nothing about failure behavior (e.g., unknown contactId) or permission requirements.

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?

One dense sentence with zero filler, and the most decision-relevant information ('full detail of a contact') is front-loaded. It is a noun phrase rather than a full clause, which is slightly terse but costs no clarity.

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 one-parameter read tool with full annotation coverage, the description adequately covers what comes back, which matters because no output schema exists. The remaining gap is error/empty-result behavior, a minor omission for a getter of this shape.

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 schema provides only the parameter name and string type. The single parameter is self-evidently an identifier, but the description adds no format, sourcing, or example detail to compensate for the coverage gap.

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 ('Get a contact') and goes further by enumerating what the payload contains (channels, tags, custom fields, notes, last interaction), which separates it from list_contacts. It does not name the sibling it is not, but 'a contact' + 'full detail' makes single-record retrieval unambiguous.

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: the singular 'a contact' and 'full detail' suggest fetching one record by ID rather than enumerating, which contrasts with list_contacts. No explicit when-to-use, when-not, or alternative is stated, and prerequisites (does the contact need to exist?) are absent.

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