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

No annotations are supplied, so the description must carry the behavioral burden, and it does state the key traits: public read access level, side effects explicitly 'None (read-only)', and a JSON return. It lacks detail on what 'active session' means when none is active or whether the values are point-in-time snapshots, which keeps it below a 5.

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?

Three short sentences, each doing distinct work: access level first, then what state is inspected with the metric names, then return format and side effects. Nothing is redundant with the name and nothing is padding.

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, annotation-free read tool with no output schema, the description supplies what an agent needs: what state is exposed, that it is safe and non-mutating, and that JSON comes back. The mathematical notation for entropy and budget is left unexplained, but that is a minor gap for a diagnostic call.

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 takes zero parameters, so there is nothing for the description to disambiguate; the baseline for a parameterless tool applies. The description correctly does not invent parameters and instead spends its words on return content.

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 names a specific verb ('Inspect') and a specific resource ('the internal state of the active session'), then enumerates the metric families returned (entropy, budget, hit rates, active node counts). That is enough to separate it from write-oriented siblings like session_control or vault_write_*. It stops short of explicitly contrasting itself with the closest read-oriented sibling, system_describe.

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 by the phrase 'active session' and the [PUBLIC READ] tag, so an agent can infer this is the tool for checking live session metrics. There is no explicit when-to-use/when-not statement and no named alternative for overlapping diagnostic needs such as system_describe or session_handover.

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