fork_join

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

Annotations already indicate this is a mutating operation (readOnlyHint false) but not destructive (destructiveHint false). The description adds specific error behavior ('Errors if the fork is unknown or already closed'), which is not covered by annotations. It does not mention success return behavior, but given the annotation coverage, this is adequate.

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 primary action, and no wasted words. The purpose, downstream link, and error conditions are packed efficiently.

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?

The description covers the core purpose and error conditions but leaves `app_id` unexplained and does not describe the success response or any side effects. Given the moderate complexity and the presence of annotations covering read-only and destructive hints, the description is not fully complete but meets a baseline. The missing app_id semantics and return behavior are notable gaps.

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 schema description coverage at 0%, the description carries the full burden of explaining parameters. It explains `component` explicitly ('an agent, repo, or subsystem name') and implies `fork_id` through the error condition, but `app_id` is left completely unexplained. The agent cannot correctly determine the semantics of all required parameters from this description.

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 action ('Register'), the resource (a fork participant), and the specific semantic of the component name. It also differentiates from the sibling fork_log by explaining the downstream use. This distinguishes it from fork_create, fork_merge, and fork_log without ambiguity.

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 explains that this is a prerequisite for logging changes via fork_log, providing context for when to use it. However, it does not explicitly state when not to use it or mention any alternatives beyond the implicit fork_log, so it lacks exclusions. Still, the context is clear and actionable.

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