list_sessions

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the safety profile is covered. The description adds genuinely useful behavioral context beyond those annotations: sessions can persist across server runs and may still be running, a non-obvious detail that affects how an agent interprets the results.

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 a single, front-loaded sentence with no filler. Every word contributes: it names the resource, states the scope is all sessions, and highlights the persistence caveat.

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 parameterless, read-only listing tool with an output schema and safety annotations, the description covers everything an agent needs to understand the call's scope. The only minor gap is explicit sibling differentiation, but the context and annotations make the behavior sufficiently complete.

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 there is no parameter burden for the description to carry. The 100% schema description coverage and empty properties object mean the description does not need to explain any inputs.

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 states the resource being listed ('All trace/replay sessions') and adds a meaningful scope detail: it includes sessions still running from a previous server run. This makes it clear it is a listing operation, but it does not explicitly differentiate itself from the sibling list_traces tool by naming the alternative.

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 phrase 'All ... including any still running from a previous server run' implies this is the broad, unfiltered session listing tool. However, there is no explicit guidance about when to prefer list_sessions over list_traces or other sibling tools, leaving the routing decision mostly to inference.

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