l402-balance

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

The description discloses key behaviors beyond the readOnlyHint annotation: it returns 'last known balance' from a credential store, performs no network request, and explains the condition for the 'stale' flag (updated more than 5 minutes ago). This adds meaningful context that annotations alone don't provide.

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 concise sentences deliver all essential information: the action, the caching behavior, and the staleness rule. Every sentence earns its place with no redundancy or filler.

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 one-parameter tool with no output schema, the description explains the return concept (balance and stale flag) sufficiently well. It stops short of detailing the full response structure or edge cases (e.g., no cached value), but given the simplicity, this is a minor gap.

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% and the only parameter 'origin' already has a clear description with a URI format and example. The description adds no additional parameter-specific meaning, so the baseline of 3 is appropriate.

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 states a specific verb and resource: 'Check cached credit balance for a server.' It distinguishes this tool from siblings by emphasizing that it uses a cached value and makes no network request, which sets it apart from other l402 tools like l402-fetch or l402-pay.

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 clearly implies when to use this tool: when you want a fast, cached balance check without network overhead. However, it doesn't explicitly name alternatives or state when not to use it, so it lacks explicit exclusions that would merit a 5.

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