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

Goes well beyond the readOnlyHint=false annotation by disclosing exactly what is created (an active membership with no auto-renew, a payment, an invoice) and that the call is confirm-gated, returning only a preview until confirm: true. It stops short of covering re-invocation behavior, what happens if the client already has an active membership, or failure/duplicate handling.

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?

A single sentence with a parenthetical gating note — front-loaded with the actor, then the effect, then the confirm requirement. No filler and nothing buried.

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 nested 3-parameter mutation with no output schema, the description covers actor scope, downstream effects and the preview/execute gate, which is the critical operational context. Gaps around conflicts (existing active membership), idempotency and error/preview response contents keep it from being complete.

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 67% schema coverage the schema already documents amount defaults, date formats and confirm semantics, so the description need only add value. It instead narrows the payment method to 'cash/UPI/bank' while the schema enum also permits CARD, DIRECT_LINK and OTHER, and it adds nothing about planId, reference, or the endDate default.

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 (record a payment from one of their own clients) and enumerates the side effects (membership, payment, invoice). The 'Solo coach' qualifier helps separate it from organization/gym desk tools, though it never explicitly names the near-identical sibling record_coach_desk_payment_with_proof that differs only by proof attachment.

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?

Scope is implied by 'Solo coach' and 'one of their own clients', which excludes org-level and gym flows. But there is no explicit when-to-use/when-not, and the closest alternative (record_coach_desk_payment_with_proof) is not mentioned, so an agent must infer the choice from tool names alone.

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