controller_checkpoint_write

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

With no annotations provided, the description carries the full burden. It discloses key behaviors: atomicity ('Atomically write'), keying by exact ROM SHA, optimistic revision protection, bounded state size, and output path ownership. It does not elaborate on failure modes or return values, but the optimistic revision mechanism implies conflict handling.

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 concise sentences with no fluff. It front-loads the action ('Atomically write') and packs relevant constraints into the first sentence. Every phrase 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?

Despite the detailed schema and strong description, the tool has no output schema and the description does not explain return values or error behavior on revision conflicts. This is a gap for a mutating tool with optimistic concurrency, though the 'optimistic revision protection' phrase implies non-overwrite on conflict.

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?

Although schema coverage is 0%, the description maps parameters to their roles: 'current exact NDS ROM SHA' explains the 'rom' parameter, 'optimistic revision protection' explains 'expectedRevision', and 'bounded provider-neutral controller handoff state' describes the 'state' object. This adds semantic meaning beyond the raw schema.

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 verb ('Atomically write') and resource ('bounded provider-neutral controller handoff state') with specific scope ('for the current exact NDS ROM SHA'). It distinguishes itself from sibling controller_checkpoint_read by focusing on write semantics and adding details like optimistic revision protection.

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 makes the tool's use case explicit: it writes handoff state, so an agent can infer when to use it (to persist controller state) versus reading via controller_checkpoint_read. However, it does not explicitly mention alternatives or exclusions, leaving some inference to the agent.

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