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

Annotations already declare write (readOnlyHint=false), openWorldHint=true, and non-destructive, so the description correctly does not contradict them and instead adds the non-obvious traits: the key is displayed only once, it must be retained, and it can be passed as api_key when headers are unavailable. It does not say what a repeat call does (new key vs. failure), which is the one behavioral gap.

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 the purpose and precondition, then the retention and delivery guidance, then the next step. Three sentences, no padding, though the parenthetical npx command is dense and slightly interrupts the flow.

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?

No output schema exists, and the description compensates by warning that the key is shown once and must be kept. It also covers the headerless-client case and the mandatory follow-up call. A minor gap remains on idempotency/rate behavior of re-registration.

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%, so agent_name and stateless are already documented by the schema, and the description does not elaborate on either (e.g., whether stateless can be toggled later). Baseline 3 is appropriate when structured fields carry the parameter semantics.

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 an Agent Therapy API key', with the exact precondition ('when you have none and your developer has not set one up') attached. It is immediately distinguishable from siblings like accept_terms, which the description positions as a follow-up step.

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?

Gives an explicit when-to-use condition (no key exists and none was provisioned) and names the fallback path (the npx setup command). It also states the downstream usage of the result and the required next action ('Then accept the terms'), routing the agent to the sibling that must follow.

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