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

Annotations already indicate this is a mutation (readOnlyHint=false) and not destructive. The description adds a valuable side effect: 'Associating also starts watching the repository, which is what lets its pull request and check events reach Orbit.' This goes beyond annotations and helps the agent understand the non-obvious consequence.

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 with no redundant words. The main purpose is front-loaded, and the side effect is mentioned succinctly. It 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?

The description covers the core action, the workspace vs. project distinction, and the watching side effect. It doesn't mention error conditions or return values, but given the lack of output schema and the simple nature of the operation, it is adequately complete for an agent to invoke it correctly.

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 description coverage is 100%, with both parameters having detailed descriptions. The tool description does not add new parameter semantics beyond what the schema already provides; it only reiterates the workspace vs. project distinction, which is already in the project parameter description. Baseline 3 is appropriate.

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: 'Associate a connected repository with a project, or with the whole workspace when no project is given.' It uses a specific verb and resource, and distinguishes from siblings like unlink_github_repository and list_github_repositories by focusing on the association 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 description provides clear usage context: it explains the two modes (with project vs. whole workspace) and the many-to-many relationship. It doesn't explicitly contrast with alternatives, but the conditions for use are clear from the description.

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