End Session

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

With no annotations, the description carries full burden. It discloses the critical behavioral trait 'nothing auto-saves; you must call this', which is vital for correct invocation. It also reveals the optional pipeline update capability. However, it does not describe idempotency or error conditions.

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 with no waste. The first sentence is an imperative warning that front-loads the most critical behavioral instruction. The second sentence concisely describes optional parameters. Every word earns its place.

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?

No output schema, so description should cover return values or side effects. It mentions that the tool persists session state and optionally updates the pipeline narrative, but does not state what the tool returns (e.g., confirmation) or whether it fails silently. The description is adequate for a simple end-point but lacks full closure.

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 83%, so baseline is 3. The description adds minimal meaning beyond existing schema descriptions—it mentions that close_phase/open_phase update the 'project pipeline narrative spine', but the schema already explains their purpose. The extra context is helpful but not substantial enough to raise the score.

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 ends a session and must be called on save/exit. It lists specific triggers like 'save, checkpoint, summarize, end, retain, or persist' which distinguishes it from sibling tools like session_start (opposite) and check/recall/remember (retrieval-focused). The verb 'End' and resource 'Session' are precise.

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 explicitly states when to use the tool (when user asks to save/end/etc.) and mentions an optional feature (close_phase/open_phase) available in the same call. It does not include explicit when-not-to-use statements, but the context of session ending is clear given sibling names.

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