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

Annotations only declare readOnlyHint=false and destructiveHint=false; the description goes well beyond them, disclosing token lifetime (expires in an hour), one-time use with a resulting long-lived credential, immutability of exclusive/repositories after registration, and the exact return shape {owner, token, expiresAt, exclusive, repositoryIds, gluecronUrl}.

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 purpose and constraints are front-loaded and every clause carries information, but the prose is dense and runs long with parenthetical asides ('a Mac for Xcode, a GPU box'), which slightly taxes scanning for an agent.

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?

No output schema exists, but the description enumerates the returned fields, covers all four parameters with behavioral consequences, and states authorization scope ('platform' as a site admin). Nearly complete for a credential-minting mutation, with only sibling-alternative routing left implicit.

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 still adds real meaning beyond the schema by giving a concrete label example ([self-hosted, macos, xcode]), stating exclusive runners never take runs-on: self / ubuntu-*, that the account keeps its shared lane, and that both flags are fixed for the runner's life.

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?

States a specific verb and resource ('Create a one-time CI runner registration token') plus the valid owner scopes, which cleanly separates it from siblings like merjax_create_deploy_token, merjax_create_repo_token, merjax_list_runners, and merjax_revoke_runner.

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?

Explains the concrete usage context — a runner started with RUNNER_REGISTRATION_TOKEN registers once and gets a long-lived credential — and describes when to set exclusive: true (Mac/Xcode, GPU box). It lacks explicit routing to alternatives such as revoke_runner or list_runners, so it stops short of full when-not guidance.

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