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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description earns credit by disclosing a non-obvious return-value guarantee: an action URL is emitted only from an exact, unexpired provider session and is never fabricated. It doesn't cover expiry behavior or what an absent session yields, which keeps it below 5.

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 sentences, front-loaded with the core behavior and followed by the one caveat worth knowing. The phrasing 'payment truth' is jargon but costs little space; nothing is padded.

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?

An output schema exists, so return values need not be enumerated, and the description still flags the most consequential output nuance (the guarded action URL). For a one-parameter idempotent read, the remaining gap is the unnamed sessionToken semantics, which is modest.

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?

The single parameter sessionToken has 0% schema description coverage, so the burden falls on the description. It adds a partial hint that the token scopes the application, but never explains token origin, expiry handling, or what an invalid/expired token returns.

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: return due and received payment status for the scoped application, which is more precise than the bare name payments.get_status. It does not distinguish itself from the several get_status siblings (applications, reservations, viewings), relying on the namespace to do that work.

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 statement of when to call this, when not to, or what alternative exists. An agent must infer from the name alone that this is the tool for checking whether a first payment has been received or is still due.

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