herdr_agent_start

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

Annotations declare destructiveHint=true, readOnlyHint=false, idempotentHint=false, and openWorldHint=false, so the agent knows this is a mutating, non-idempotent operation. The description adds little beyond this—it doesn't explain what makes it destructive (e.g., does it occupy the pane entirely, terminate existing processes?), whether restarting the same name is safe, or what happens on failure. Some value added but not rich.

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?

Single, front-loaded sentence with zero waste. It states exactly what the tool does in minimal words.

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 non-idempotent, destructive tool with no output schema, the description should do more: it lacks information about return values, failure modes, what happens to the pane on agent exit, and usage relative to siblings. The schema covers parameters well, but behavioral context is thin.

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%, so the schema fully documents all 5 parameters. The description adds no parameter meaning beyond what's in the schema—it doesn't clarify the relationship between name, kind, and pane_id, or how agent_args interacts with the startup process.

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?

Clear verb+resource: 'Start a coding agent in an existing available shell pane.' It specifies the action (start) and the target (coding agent), distinguishing it from siblings like herdr_agent_send_keys or herdr_open_agent. However, it doesn't explain what 'available' means or differentiate from herdr_open_agent, which likely also creates agents.

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 word 'existing available shell pane' implies a precondition (the pane must already exist and be available), but there's no explicit when-to-use guidance or comparison to alternatives like herdr_open_agent. The agent must infer that this tool requires a pre-existing pane while herdr_open_agent might handle creation.

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