list_sessions

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

No annotations are provided, so the description carries the full behavioral burden. It does signal read-only behavior ('read-only evidence store'), but omits pagination behavior (there is a page parameter), filtering semantics, error conditions, and result shape. For a 5-param list tool with zero annotation coverage this is thin.

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?

A single front-loaded sentence with no filler. It is concise, though partly because it omits required information rather than because it is efficiently packed.

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?

No output schema, no annotations, and 5 undocumented parameters mean the description must do much more than it does. It lacks any coverage of filtering, pagination, return contents, or trusted-state semantics.

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 description coverage is 0% and the description names none of the five parameters. Parameters like page, start_ns, end_ns, trust_state, and db are undocumented in both schema and description, so an agent must guess at their meaning and formats.

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 verb and resource ('List ... session summaries') which is clear enough, but there are many session-related siblings (get_session, get_session_manifest, list_incidents) and the description does no sibling differentiation. The added qualifiers 'deterministic' and 'read-only evidence store' hint at scope but don't distinguish it from get_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?

No when-to-use, when-not-to-use, or alternative routing is given. An agent cannot tell from this sentence why it would call list_sessions instead of get_session or get_session_manifest.

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