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

With no annotations, the description carries the full burden and does so well: it discloses cumulative cost (1 CRD per call, charged even on rejection), the 429 exception that costs nothing, the 400 REDIRECT_NOT_ALLOWED failure mode, the reusability of an existing account, and the request_id in error results. This is exactly the behavioral context an agent needs before a billed mutation.

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 dense sentences, front-loaded with purpose, then integration hint, then constraints and cost. Nothing is padded and the highest-value operational facts (redirect rules, CRD charge) appear before any conditional edge cases.

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?

There is no output schema, and the description compensates by naming both key returns (onboarding URL and acct_… stripe_account_id). For a billed, error-prone onboarding mutation with 8 parameters, it covers requirements, cost, failure modes, and downstream usage without meaningful gaps.

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 the baseline is 3, but the description adds real constraints beyond the schema for return_url and refresh_url (must be https on a Cred host or an allowed redirect domain, or the call fails with 400). It also implies why user_id/user_email matter by describing the account as tied to an end user, though it does not disambiguate user_id vs user_email usage.

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 opens with a precise verb+resource+outcome: "Create (or reuse) a Stripe Express connected account for an end user and return an onboarding URL." It distinguishes the tool from nearby siblings like create_user or redeem_credits by naming the downstream handoff (stripe_account_id as destination for redeem_credits).

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?

It clearly states what the tool produces and how to use the result with redeem_credits, and gives the redirect-URL prerequisites (https on a Cred host or an allowed redirect domain). It stops short of naming an explicit alternative or a "do not use when" condition, so it is strong context rather than full routing guidance.

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