self_update

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

The description goes well beyond the annotations by detailing refusal conditions, the exact operation sequence (pull, build, verification, restart), and the post-restart handshake. It also discloses that the call returns before the restart completes and instructs polling runtime_info, which is critical 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?

Three dense sentences carry all essential information with no filler. The privileged nature and required environment variable are front-loaded, followed by refusal conditions and then the action sequence and return behavior.

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 complex, destructive autonomous operation with no output schema, the description is remarkably complete: it covers prerequisites, failure conditions, the mutation sequence, restart behavior, and the expected follow-up action. An agent has enough to decide whether to invoke it and what to expect.

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?

The tool has zero parameters and the schema documents 100% coverage. There is no parameter ambiguity to resolve, so the description appropriately adds no parameter-level detail. The baseline for a zero-parameter tool is satisfied.

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 names a specific verb and resource: an autonomous self-update via fast-forward-only pull, build, verification, and supervised restart. It clearly distinguishes this from simple restart or status tools by describing the full update pipeline.

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 gives clear usage context: this is a privileged update path that requires MCP_ALLOW_SELF_UPDATE=1 and refuses under specific repository conditions. It does not explicitly name alternative tools or state when not to use it, but the preconditions and refusal conditions effectively define appropriate usage.

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