list_sessions

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

Annotations already declare readOnly/idempotent/non-destructive, so the safety bar is low. The description adds real behavioral context beyond that: what the result contains (liveness and port), the existence of a 'default' session alongside named ones, and the per-session isolation guarantee. No return-format or failure behavior is described, keeping it out of 5 territory.

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 tightly written sentences, with the core behavior front-loaded and the multi-board tip second. The second sentence is arguably about other tools rather than this one, but it earns its place by explaining the session argument the agent will reuse everywhere.

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-required-param, read-only listing tool with annotations covering the safety profile and no output schema, the description covers what is returned (liveness, port) and the naming model. Nothing essential for calling it correctly is missing; only failure/empty-list behavior is unstated.

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 coverage is 100%, so baseline is 3. The description nevertheless adds non-obvious semantics: the session name may be any arbitrary string and each name yields fully isolated state, which the schema's one-line description does not convey.

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?

States a specific verb and resource ('Lists all debug target sessions') and adds scope detail — the default plus any named — plus what each entry shows (liveness and port). It does not name the closest sibling (get_session) for a single-session lookup, so differentiation is implicit rather than explicit.

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 second sentence explains the multi-session model and how to pass 'session' to any tool, which is genuinely useful context. But it never says when to call list_sessions versus get_session, session_diagnostics, or recover_session, so the guidance for choosing this tool is only implied.

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