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

Annotations already declare readOnlyHint=false and openWorldHint=true, so the description's job is to explain the side effects implied by a non-read-only, open-world call. Instead it uses 'Returns', which reads like a passive read, and says nothing about whether calling it mints a persistent payment intent, whether repeated calls are idempotent, or whether links expire. The 'card or crypto, depending on what is enabled' note adds genuine context, but the mutation semantics remain undisclosed. Not a hard contradiction with readOnlyHint=false, but the framing understates the write behavior.

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?

Two short sentences, front-loaded with the core action and with zero redundant filler. The second sentence about an assistant paying itself is slightly tangential but is plausibly useful context for an agentic payment flow. Nothing needs trimming, though the title/name mismatch adds noise the description does not resolve.

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?

With no output schema, the description is the only place an agent can learn what comes back, yet it never specifies the return shape, expiration, or whether the link is single-use. Combined with no annotation-level detail on side effects for an open-world, non-read-only tool, and no guidance on the auth fallback for api_key, key information is missing. What is present is accurate but insufficient for correct invocation.

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 description coverage is 100% across all three parameters, so order_id, method, and api_key are already documented in the schema. The description adds no further meaning to any of them, including no hint about how 'method' maps to the card-or-crypto behavior it mentions. Baseline 3 applies when the schema carries the parameter burden.

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 names a specific resource and outcome: it returns a payment page for a given order, with card or crypto depending on what is enabled. That is clear enough to act on, but it never resolves whether the result is a URL, a link, or rendered page content, and it does not differentiate the tool from siblings like order_status or my_tools. The name/title/description also pull in different directions (create_payment vs. 'Get the payment link' vs. 'Returns').

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?

There is no when-to-use or when-not-to-use guidance, no mention of prerequisites such as needing a completed order, and no named alternative among the many siblings. The only usage-adjacent sentence ('an assistant that can pay may pay itself') describes who pays rather than when an agent should call this tool. An agent must infer the trigger condition entirely.

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