launch_instance

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

With no annotations, the description carries full behavioral burden, and it largely succeeds. It discloses that launch is synchronous ('wait until it answers'), that ports are auto-selected to avoid collisions, that the bridge owns the process and reaps it on shutdown, that it reads the project's gamebridge.json, and that the tool returns a port. These are exactly the behavioral details an agent needs beyond the schema.

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?

Every sentence earns its place. The description is front-loaded with the core action and wait behavior, then explains port auto-selection, process ownership, config source, return value, and provides a usage recommendation. It is compact, well-organized, and free of filler.

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 tool with two optional parameters and no output schema, the description explains the key runtime contract: the launched process lifecycle, how the port is chosen, what the return value is for, and why the tool should be preferred over manual startup. An agent has enough context to select and call the tool correctly, including what to do with the returned port.

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 schema already documents both parameters (port and timeoutMs), so baseline is 3. The description adds meaningful context beyond the schema: the bridge automatically picks a free port, so forcing one is rarely needed, and the returned port must be passed to all other tools. This helps an agent understand when and why to use or omit the optional port parameter. Timeout semantics are left mostly to the schema, but the description's 'wait until it answers' supports the intent.

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 starts with a clear, specific verb and resource: 'Start a game instance and wait until it answers.' It also distinguishes itself from starting the game manually and, by mentioning the returned port that every other tool needs, it implicitly differentiates from listing/stopping/logging tools. This is unambiguous and not a tautology.

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: it is the preferred way to launch the game, the bridge handles port allocation, and the tool waits until the game responds. It explicitly says 'Prefer this over starting the game yourself,' which is strong guidance. It does not enumerate exact when-not-to-use conditions for each sibling, but the context is sufficient for an agent to choose it appropriately.

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