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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description doesn't repeat those. It does add the behavioral context that this is for verifying webhook origin, which is useful. However, it doesn't describe return values, side effects, or any error conditionshering to the validation. Given the annotations cover safety, a score of 3 is appropriate; the description adds a bit of value but could be more explicit about outcomes.

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?

The description is extremely concise (one sentence) and directly addresses the main purpose and key argument. It front-loads the most important information. No fluff, but it is perhaps too terse to earn a 5; it could add a brief note on what the function returns or the broader context.

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 simple read-only validation tool with no output schema, the description is reasonably complete. It explains the purpose and the required parameter. However, it omits the optional 'account' parameter and does not mention what the response looks like (e.g., boolean, object, error codes). Given the low parameter coverage and lack of output schema, a bit more detail would be expected, hence a 3.

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 schema has two parameters ('account' and 'account_token'), but the description only explains 'account_token' and entirely ignores 'account'. With 0% schema coverage, the description should clarify each parameter's meaning agendas. It mentions 'account_token' in the description but not 'account', leaving ambiguity. This is a gap in parameter clarification, so it scores low.

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 clearly states the tool validates a Guru account token and explains its purpose (verifying webhook origin). It uses a specific verb ('validates') and a clear resource ('Guru account token'), which distinguishes it from the many other guru_* tools. However, it doesn't explicitly differentiate from the sibling 'authenticate' or other validation-like tools, which keeps it from a 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 a concrete use case ('used to verify webhook origin'), which helps an agent decide when to use it. However, it does not mention when not to use it or recommend alternative tools, nor does it describe any prerequisites or context for invocation. It provides basic context but no exclusionary guidance.

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