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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description earns credit for adding non-obvious behavior the annotations cannot express: results may contain end-user personal data and must be quoted minimally with identifiers masked, plus the locator-based handoff to fetch.

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, both load-bearing: the first front-loads the action, scope, and output shape; the second carries the PII-handling constraint. No filler, no repetition of schema or annotation content.

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 prose explanation, and the description covers scope and the PII constraint. What is missing is navigational context: no mention of pagination via cursor, of how locators are consumed by fetch, or of how this differs from the list_* siblings.

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 92%, so the schema already documents query, cursor, limit, namespace_id, filters, and the required telemetry fields. The description adds no syntax, defaults, or interaction detail beyond that, making the baseline 3 appropriate.

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 a specific verb and resource (search one Flowlines namespace) and characterizes the return (citation-ready results with opaque fetch locators), which points at the fetch sibling. It does not explicitly distinguish itself from the many retrieval siblings (list_sessions, get_session, fetch), so it falls short of a 5.

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: 'Search one Flowlines namespace' tells the agent this is the evidence-retrieval entry point, and 'opaque fetch locators' hints that fetch is the follow-up call. There is no explicit when-to-use/when-not, no named alternative, and no prerequisite guidance (e.g. when to prefer list_sessions or aggregate_sessions).

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