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

With no annotations, the description carries the full burden of disclosing side effects. It explicitly says that ending the session triggers context block generation, where activities are summarized and stored in the knowledge graph. This is meaningful behavioral context beyond the simple action of ending a session, though it does not mention other potential side effects like irreversibility or permission requirements.

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 two sentences, with the primary purpose in the first sentence and a key side effect in the second. It is front-loaded, concise, and contains no extraneous information.

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 has no output schema, but the description explains the purpose and a significant side effect (context block generation). It provides enough context for an agent to decide when to use the tool and what to expect. It does not detail return values, but with no output schema declared, this is a minor gap given the tool's straightforward nature.

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?

The input schema already provides descriptions for all three parameters (outcome, session_id, token_usage), achieving 100% schema coverage. The description does not add parameter-specific semantics beyond the overall context of summarizing activities, so the 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 clearly states the tool's function: 'End a work session.' It also adds a distinguishing detail about triggering context block generation, which sets it apart from sibling tools like 'start_session' or 'list_sessions'. The verb+resource combination is unambiguous.

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 the usage context: this should be called when a work session is being ended. However, it does not explicitly state when to use it versus alternatives, nor does it mention any exclusions or prerequisites. The guidance is present but implicit.

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