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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds genuine non-annotation context: the operation is permissionless and requires no key, which is exactly the kind of auth information an agent needs before calling.

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, the core check front-loaded and the access caveat second. No filler or restatement of the title.

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 single-parameter tool with no output schema, the description should convey what a verification result looks like (valid/invalid, expiry, signature failure) and it does not. Annotations carry the read-only safety profile, but the return semantics gap keeps this merely adequate.

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?

There is one required parameter with 0% schema description coverage. The description only implies that 'token' is a Spend Gate token and does not state its format (opaque string, JWT, encoded payload) or where it is obtained, so it compensates only marginally.

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 (check/verify) and resource (Spend Gate token), and further specifies the two things checked: signature validity and remaining spendability. This cleanly separates it from siblings like sebbi_spend_request or sebbi_spend_policy, though it never names an alternative directly.

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 rather than stated: you verify a token before relying on it. The sentence 'Anyone can call this; no key needed' addresses authorization, not when-to-use versus alternatives such as sebbi_spend_request or sebbi_verify_chain. No explicit when-not guidance.

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