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

Adds the single most important fact the annotations cannot convey: the old provider link stops working immediately, and the caller must push the returned entry_url to the provider — that is exactly the consequence implied by destructiveHint=true. It also documents replay semantics (unique key, reuse on timeout) and a recovery path via get_external_panel. There is a mild surface tension with idempotentHint=false, but the description is describing key-scoped replay safety of a non-idempotent operation, not contradicting the annotation.

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?

Three sentences, each earning its place, with the destructive effect front-loaded before the recovery instructions. No preamble, no repetition of the title.

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?

Output schema exists, so return values need not be explained; annotations cover the safety profile; the description covers the destructive side effect, the provider-side follow-up, and retry behavior. Nothing an agent needs in order to call this correctly is missing.

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 schema coverage at 67%, the schema already documents idempotency_key and organization_id, and the description largely restates the key-reuse rule rather than adding format or constraint detail. It does add the 'owned study' ownership framing for study_id, but offers no extra semantics for organization_id/billing selection.

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 precise verb+resource+scope: 'Replace the external-panel entry token for an owned BYOP study.' An agent can immediately distinguish this from get_external_panel (reads the link) and delete_external_panel (tears the panel down) without opening any schema.

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 clear situational guidance plus an explicit alternative: 'inspect the current link with get_external_panel if the replay is stale,' and tells the caller to reuse the idempotency_key after an uncertain response. It stops short of an explicit exclusion (e.g. 'do not use this to configure or remove a panel — use configure_external_panel / delete_external_panel'), so it is clear context rather than full when/when-not routing.

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