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

No annotations are provided, so the description must carry the full burden. It discloses internal steps (parses plan, creates tasks, starts mission with budget/time limits) and mentions the return value (mission status string). It could mention side effects like cost usage, but the schema covers budget limits. Overall, good behavioral context.

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 long with a clear 'WHEN TO USE' marker. It is front-loaded with the core purpose, followed by behavioral details. No extraneous content.

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?

Given the tool has 4 parameters and an output schema, the description adequately explains the internal process (parsing, task creation, mission start) and return value. The output schema covers return details, so the description is complete enough without needing to elaborate further.

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 coverage is 100%, so baseline is 3. The description mentions budget and time limits, but the schema already describes these as 'Mission spend cap' and 'Mission time cap.' The description reinforces but does not add significant new meaning beyond the 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 'Execute a plan file autonomously,' which is a specific verb-resource pairing. It distinguishes from sibling tools like nucleus_plan_import (which imports but does not execute) and nucleus_plan_list (which lists plans), making the purpose 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 includes a 'WHEN TO USE' condition: 'you have a plan file (.brain/plans/*.md) you want executed autonomously.' This provides clear context but does not explicitly mention when not to use or name alternative tools, though the sibling list implies alternatives.

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