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

With no annotations, the description carries the burden of behavioral disclosure. It conveys that the tool reports session state and related windows, implying a read-only lookup, but does not explicitly state that it is non-destructive, nor mention any timing/caching nuances. This is acceptable for a zero-param getter but not rich behavioral context.

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 one dense, front-loaded line with no filler. Every phrase — 'open/closed', 'force-flat time', 'lane windows' — adds information. It is an appropriately sized definition for a simple no-argument getter.

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 zero-parameter tool with an output schema, the description reasonably covers the semantic categories returned. It doesn't explain the meaning of 'force-flat time' or 'lane windows', but the output schema can carry return-value detail. It lacks usage context, though that is already penalized under usage guidelines.

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 are zero parameters and schema coverage is 100%, so the description has no parameter semantics to add. The baseline of 4 is appropriate because there is nothing missing for invoking the tool with an empty argument object.

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 identifies the resource ('session state') and enumerates the specific outputs it provides: open/closed, force-flat time, and lane windows. Although it is a noun-fragment rather than a full verb phrase, the tool name starts with 'get', so the action is unambiguous. It is specific enough to distinguish it from other market-data siblings.

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?

No guidance is given about when to use this tool versus sibling tools, and no alternatives or exclusions are mentioned. The agent must infer from the name and output fields that this is the go-to source for session clock status, which is not explicitly stated.

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