train_start

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

With no annotations, the description carries the full burden and does add real behavioral context: it is asynchronous ('returns at once'), container-isolated, and explicitly independent of the daemon and the MCP session. It still omits failure behavior, resource/GPU requirements, and any concurrency limits.

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?

Front-loaded purpose followed by tight per-parameter notes; each sentence adds information. The trailing 'Independent of the daemon...' line is slightly disconnected but still 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?

An output schema exists so return values need not be explained, and the description covers the async launch semantics and the most ambiguous parameters. The gaps are the four undocumented params and the absence of any sibling routing, which for an 8-param async launcher is a modest shortfall rather than a serious one.

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 0% across 8 params, so the description must compensate and it only does so for half: task (gym id + example), run_name (default pattern + retention purpose), extra_args (verbatim + Hydra example), device (GPU index). seed, num_envs, checkpoint, and max_iterations are left to their self-explanatory names.

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 ('Launch a headless Isaac Lab training run in its own container') with the key scope fact that it returns at once. This is clearly distinguishable from the sim_* control tools and from the train_status/train_logs readers.

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?

Usage is implied by 'keep it [run_name] to find the run later', which gestures at train_status/train_logs, but no sibling is named and there is no explicit when-to-use or when-not-to-use guidance. An agent can infer intent but is not routed.

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