List terminal sessions

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

Annotations only cover the safety profile (readOnly, idempotent, non-destructive); the description goes well beyond them by disclosing that tombstones are reservations whose shell is gone, that calling one respawns a fresh shell and surfaces the original termination reason (shell-exit, idle-killed, evicted), and that tombstones expire after 30 days. This is exactly the non-obvious behavior an agent needs.

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 sentences, front-loaded with the core purpose, followed by the tombstone semantics that are impossible to infer from the name or schema. No filler; every sentence carries information an agent would otherwise lack.

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?

With no output schema, the description must describe the return shape, and it does: the two categories of returned ids plus the termination-reason enum values. Combined with the rich tombstone lifecycle explanation, nothing material is missing for a zero-parameter list tool.

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 the baseline is 4. The description correctly adds no parameter detail because there is nothing to parameterize.

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 (List) and resource (terminal sessions), and immediately clarifies the two result categories: active sessions and tombstoned sessionIds. That distinction cleanly separates it from sibling tools like terminal_create or terminal_read, which act on a single session.

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?

Listing is self-evidently the discovery entry point, and the description implicitly signals a use case by explaining that a tombstoned id can be called again. However, it never explicitly states when to reach for this tool versus a sibling (e.g. to discover a sessionId before terminal_read), nor does it name any alternative.

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