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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered. The description goes beyond them by disclosing two real operational constraints the annotations cannot convey: a Last Price credential is required, and an unclaimed workspace returns 403 until a person claims it — a failure mode an agent would otherwise misdiagnose.

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?

Front-loaded with purpose and return fields, then requirements; every sentence carries information. "Pass contact_id" mildly duplicates the required field in the schema, a small redundancy in an otherwise tight definition.

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-param read tool with no output schema, the description covers the return shape, the auth requirement, and the notable error condition, which is enough to call it correctly. It stops short of stating what happens when the id does not exist (404 vs empty), the only material gap.

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?

With 100% schema description coverage and a single required param, the schema already carries the meaning (including the hint that the id matches what list_contacts shows). The description only restates "Pass contact_id" and adds no format or sourcing detail beyond the schema.

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+resource ("Read one contact") and enumerates the fields returned (name, email, phone, address, external id, metadata), making the scope concrete. The instruction to pass contact_id implicitly separates it from get_contact_by_external_id and list_contacts, but those siblings are never named.

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 implied by the single-record scope and the id-based lookup, and prerequisites for a successful call are spelled out. However, it never says when to prefer this over get_contact_by_external_id, list_contacts, or update_contact, so the agent must infer.

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