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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world, so safety is covered. The description adds genuinely new context beyond that: results may contain end-user personal data, with an explicit instruction to quote minimally and mask direct identifiers. It doesn't describe the cursor contract's failure modes or page-size ceilings, which the schema covers anyway.

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 sentences, purpose front-loaded, zero filler. The second sentence is a distinct and material handling constraint rather than 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?

With an output schema present, return values need no explanation, and the description covers scope, filtering, pagination, and data-sensitivity. It stops short of explaining filter combination semantics (AND vs OR) or how cursors are obtained from a prior response, minor gaps for a 12-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?

Schema description coverage is 100% and every one of the 12 parameters is documented in-schema, including the exclusive `to` boundary, `limit` default, and enum semantics for `outcome`/`user_feedback`. The description adds only the generic phrases 'API filters' and 'cursor pagination' and no parameter-specific meaning, so baseline 3 is correct.

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 ('List sessions'), scopes it ('in one Flowlines namespace'), and names the mechanism ('API filters and cursor pagination'), which implicitly separates it from aggregate_sessions and search. It never names a sibling explicitly, so an agent must still infer the boundary against search/aggregate_sessions/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?

Usage is only implied by the namespace scoping and pagination mention; there is no statement of when to prefer this over search, aggregate_sessions, or get_session, and no exclusions. The PII sentence is a handling instruction, not a selection guideline.

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