Close a session

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

With no annotations, the description carries the burden. It discloses the primary side effect (writing a digest file to a specific location), which is valuable. However, it does not mention whether the session is marked as closed in any backend state, whether the operation is idempotent, or any permission requirements. The single disclosed side effect is helpful but incomplete for a mutation-like closing action.

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, immediately front-loaded with the usage trigger, then the primary effect. Every word earns its place; no fluff.

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 with all parameters required and well-documented in the schema. The description explains the key output side effect and usage context, which is sufficient for an agent to call it correctly. No output schema exists, but the return value is likely trivial. Losing a point because no annotations exist and the description does not cover state mutation or post-conditions, but overall it is complete for the operation's purpose.

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%, so the baseline is 3. The description adds no parameter-level detail beyond what the schema already provides (e.g., sessionId from start_session, summary narrative, openThreads list). The schema descriptions are sufficient, so no deduction is needed.

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 action ('Call this when...' + 'Writes a human-readable digest to .diffmind/digests/<sessionId>.md'), describing a specific verb (close) and resource (session digest path). It does not explicitly name sibling tools like start_session, but the trigger phrase 'when the work is done or the conversation is ending' implies the distinction. Thus it is clear but lacks explicit sibling differentiation.

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?

Provides explicit when-to-use guidance: 'Call this when the work is done or the conversation is ending.' It does not explicitly discuss when not to use or name alternatives, so it misses the top score, but the context is unmistakable.

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