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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is covered structurally. The word "immediately" adds a real nuance (no graceful drain or wait), but the description does not say what is lost on termination or whether the session can be resumed, which is the key behavioral unknown for a destructive call.

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 zero filler, which suits a simple one-parameter action. It is on the edge of being too sparse, but no wording is wasted.

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 one-parameter destructive tool whose annotations already carry the safety signals, this is close to adequate. The remaining gap is the effect of the call: what happens to the session's state and whether the id remains valid afterwards, which matters for a destructive stop.

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 coverage is 100% and the session_id property already documents that the value comes from start_session, so the baseline is 3. The description adds nothing further about the parameter, such as what happens when passing an already-stopped id.

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?

A clear verb plus resource ("Stop the session") that an agent can immediately distinguish from start_session and get_session. It stops short of 5 because it doesn't contrast with any sibling on scope or semantics beyond the adverb "immediately".

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 gives no when-to-use guidance at all: nothing about calling it before start_session again, what happens to in-flight work, or when a graceful alternative is preferable. The intent is only implied by the tool name.

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