end_visual_session

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

With no annotations, the description carries the full burden and does so: it discloses the exact return behavior (typed TOOL_REMOVED error plus a migration recipe pointer) and the lifecycle semantics that replaced it. An agent knows calling this is a no-op that yields a structured error, not a state mutation.

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 removal notice is front-loaded in brackets before any explanation, and each subsequent sentence earns its place by naming the error type, the two replacement mechanisms, and the migration docs. No 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?

For a deprecated stub with no output schema, the description covers everything an agent needs: don't call it, what happens if you do, and exactly what to do instead, including doc pointers.

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 the enum on reason is documented in-schema, so the baseline is 3. The description adds no parameter-level detail beyond what the schema already states, which is acceptable given the tool is a removed stub.

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 immediately and unambiguously states the tool's current status and behavior: it was removed in v0.9.0 and calling it returns a typed TOOL_REMOVED error. This is a specific, actionable purpose that an agent can distinguish from start_visual_session and every action tool without opening a schema.

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?

It explicitly says when NOT to use this tool and names the alternatives: sessions now clear automatically after 60s of silence or immediately when an action tool is called with is_final: true. That is a complete routing instruction with no inference required.

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