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

With annotations only covering readOnly/openWorld/idempotent, the description carries the real behavioral burden and does so well: exact cost and rails (0.001 RLUSD on xrpl:0 or 0.001 USDC on Base eip155:8453), 60 s cache, unpaid-call-is-free, the isError + fresh invoiceId behavior, and that openai/cursor keys return null until 2026-11-12. This is exactly the kind of context annotations cannot express.

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?

Payment rails and cost are front-loaded, then output shape, then failure/retry semantics, which is the right order. It is dense and slightly redundant (affiliation disclaimed twice; unpaid-call wording overlaps the isError sentence), but nearly every sentence carries operational weight.

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, yet the description enumerates the response fields (level, reason, indicator, asOf, sources with attribution, terms_url, affiliation notice). Combined with the error/retry path, cost, and caching behavior, an agent has everything needed to call this correctly on the first attempt.

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 meaning beyond the schema: the signed payload can arrive via _meta["x402/payment"] OR payment_signature, and the parameter should be omitted on the first call to receive payment requirements. That sequencing nuance is not in 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 and resource: it summarizes public AI-provider status pages via the Statuspage API (GitHub, Anthropic) and enumerates the returned fields (level, reason, per-provider indicator, asOf, sources, terms_url). That is far more specific than the title alone. It stops short of explicitly distinguishing itself from close siblings such as decide_provider_health or get_service_status, so it lands at 4 rather than 5.

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?

The description gives clear invocation guidance for the payment handshake: the first unpaid call returns isError with a PaymentRequired object, and the retry must carry the signed payload in _meta["x402/payment"] or payment_signature. However, it never says when an agent should choose this tool over siblings like decide_provider_health, decide_cheapest_model, or get_service_status. Usage context is present for the payment flow but absent for tool selection.

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