Report persisted session status

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

With no annotations, the description must carry behavioral transparency. It states the tool checks for a session 'on disk' which adds useful context about side-effect-free inspection. However, it does not clarify what 'usable' means, how the result is returned (e.g., boolean, object), or whether any network/auth is involved. This is minimal but not misleading.

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 two concise sentences: the first states the core function, the second adds usage guidance. No wasted words, front-loaded with the most important information. This is ideal for a simple status-check tool.

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?

Given the tool's low complexity (0 params, no output schema), the description is fairly complete. It covers what it does and when to use it, implying a boolean result via 'Whether.' It does not specify the exact output format or session validity criteria, but for a simple check this is acceptable.

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, and schema description coverage is 100% (empty schema). The baseline for 0 params is 4. The description adds no parameter details because none exist, but it gives enough context about what the tool evaluates.

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's function: checking whether a usable balance.it session exists on disk. This is a specific verb+resource combination that distinguishes it from recipe/calorie sibling tools. The title 'Report persisted session status' aligns with the description.

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 explicitly gives usage context: 'Useful to distinguish "dead session" from "real failure" before running slower tools.' It indicates when to use this tool (as a pre-check) and implies an alternative (slower tools). It lacks an explicit 'when not to use' but the context is clear enough.

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