vibe_run

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

With no annotations, the description carries the full burden. It discloses the return payload (parsed JSON, session id, exit classification, cost/turn summary), which is useful, but it never states that this launches an autonomous agent that can read and modify files in the project directory, that it is long-running, or what approval semantics apply by default.

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?

Two tight sentences, front-loaded with the action and resource, then the return shape. No filler or repetition.

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 14-parameter tool with no annotations and no output schema, the description covers purpose and return values but omits side effects, default approval behavior (auto_approve defaults false, agent profiles), and lifecycle concerns like time limits. An agent could call it without knowing it may mutate the working tree.

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% and each parameter is documented inline with its CLI flag, so the description adds nothing beyond the schema. Baseline 3 applies; the description mentions only prompt and project directory, both already covered.

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 gives a specific verb and resource: 'Start a new Mistral Vibe coding-agent session,' plus the required prompt and project directory. It distinguishes itself from vibe_resume only implicitly via 'new,' rather than naming the sibling or its boundary.

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?

'Start a new ... session' implies this is for beginning rather than continuing work, which hints at when to use it versus vibe_resume, but there is no explicit when/when-not guidance, no mention of prerequisites (git repo, auth, trust), and no routing to vibe_manage.

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