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

The description claims a state-changing action ('Start or resume') while annotations declare readOnlyHint=true. This is a direct contradiction. An agent would be misled about whether the tool mutates session state, and no additional behavioral traits (e.g., side effects, response format) are disclosed beyond the annotation conflict.

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 sentence that front-loads the core action and purpose without any fluff. Every word contributes to understanding the tool's role.

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?

The tool is simple and has an output schema, but the contradicting annotations and lack of explicit usage guidance leave an agent uncertain about side effects and when to choose this tool. The read-only mislabel is a significant completeness gap that outweighs the simplicity.

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% for both parameters (user and title), so the schema already documents them. The description adds no extra meaning about parameter usage or formatting, so a baseline of 3 is 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 action ('Start or resume'), a clear resource ('agent session'), and an explicit purpose ('persistent continuity across tool invocations'). This is unambiguous and easily distinguishable from sibling memory tools, and even from 'session.continuity' which implies a different operation.

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 description implies usage context ('for persistent continuity across tool invocations') but does not explicitly state when to use this tool versus alternatives like 'session.continuity' or memory tools. It offers no exclusions or alternative routing, so guidance is present but not comprehensive.

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