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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds valuable context beyond those: it discloses the data source ('the file the code itself obeys') and clarifies that a stopped lane is stopped by decision, not broken – an important interpretive nuance that prevents misinterpretation. This exceeds what annotations 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. The first states purpose and data source in a front-loaded manner; the second adds a meaningful clarification about stopped lanes. The phrase 'Free, keyless, read-only' is a short, useful note about access, adding no unnecessary length. Every word earns its place.

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 parameters and an output schema available (indicated by 'has output schema: true'), the description covers purpose, data source, and interpretation of results ('and why', 'stopped by decision'). It is complete for an agent to decide when to invoke it and to correctly interpret the response. No essential information is missing.

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 tool has zero parameters, so the schema coverage is trivially 100%. The description appropriately omits parameter details, meeting the baseline for zero-parameter tools. No additional parameter explanation is needed.

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 reports whether each recurring-spend lane is running or stopped, and why, sourced from the configuration file the code obeys. It distinguishes itself from all siblings by focusing on 'recurring-spend lanes', a concept not covered by any other tool. The title reinforces the purpose.

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 implies usage by specifying the authoritative data source ('read from the file the code itself obeys'), making it clear this is the canonical source for lane status. While it does not explicitly name alternatives or exclusion conditions, the 'recurring-spend lane' concept is unique among siblings, so an agent would correctly select this tool for such queries. Missing explicit 'when not to use' guidance is a minor gap.

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