Record where this session stopped

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

Annotations only signal that this is not read-only, not idempotent, and not destructive. The description adds valuable behavioral context: it appends to an append-only ledger, stages a note, and has a downstream effect (next bootpack inherits it). It does not fully detail all side effects or return behavior, but it goes beyond the annotations.

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, front-loaded with the core action, then side effects, then policy. Every clause earns its place and the doctrine is memorable guidance rather than filler.

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 three-parameter tool with no output schema, the description is nearly complete: it covers what happens, the downstream effect, and the recommended usage threshold. The only notable gaps are naming sibling tools for disambiguation and explaining the trigger enum values, neither of which is critical.

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?

With only 67% schema description coverage and trigger lacking a description, the description compensates by mapping telemetry to usage %, trigger, and what was cut. usage and cut are already documented in the schema, and the description adds the unifying telemetry framing, though it adds little detail to the trigger enum.

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 opens with a specific verb and resource ('Record a session boundary') and details exactly what the tool does: appends telemetry to the append-only handoffs ledger and stages a handoff note that the next bootpack inherits. This clearly separates it from siblings like retrieve and bootpack by focusing on the boundary-recording action.

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 doctrine line gives concrete when-to-use guidance: hand off at ~88-90% and do not ride to the wall, so an agent knows the intended invocation point. It does not name alternative tools or explicitly say when not to use it, so it stops short of a 5.

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