payware_authentication_validate_jwt

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

Annotations already declare readOnly, idempotent and non-destructive, so the safety profile is covered. The description goes beyond that by disclosing the actual rule set being enforced — algorithm, audience (including the ISV on-behalf form), 5-minute freshness, and conditional contentSha256 verification — which tells the agent what failure modes to expect. It does not describe whether failures surface as errors or as a structured result, which is the remaining gap.

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 front-loaded sentence opens with the merchant scope and the core verb, then lists the checks in a compact parenthetical. Every clause carries information; the only mild cost is that the parenthetical list makes the sentence dense and slightly harder to scan than a short bulleted structure would be.

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 must convey what the agent gets back, and enumerating the decoded header/payload plus each checked claim gives a good proxy for the result contents. It is silent on how an invalid token is reported (thrown error versus a result flag), which is the one thing an agent would still have to discover at call time.

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%, so both parameters are already documented, including the POST/PUT/PATCH-versus-GET/DELETE rule for expectedPayload. The description corroborates that contentSha256 is checked against the supplied body but adds no syntax, format, or edge-case meaning beyond the schema. Baseline 3 is appropriate when the schema carries the parameter detail.

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 gives a specific verb ('Validate and debug') and a specific resource (a payware JWT), then enumerates exactly what validation means: decoding header/payload, checking algorithm, audience including the ISV on-behalf form, 5-minute freshness, and contentSha256. That is far more than a restated name. It stops short of naming which sibling to use instead (e.g. payware_authentication_test_jwt or payware_authentication_create_jwt_token), so the differentiation is implicit rather than stated.

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?

Usage is implied by the 'when one is given' clause and by the schema note telling callers to supply expectedPayload for POST/PUT/PATCH and omit it for GET/DELETE. There is no explicit statement of when to reach for this tool versus test_jwt or create_jwt_token, and no mention of prerequisites such as needing an existing token first. Adequate but leaves the alternative-selection decision to inference.

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