render_info

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

Beyond the annotations (which already cover read-only/idempotent/non-destructive), it discloses cost and resource behavior ('no GPU time, no charge'), the auth source (JANCTION_RENDER_API_KEY or ~/.janction-render.json, auto-provisioned), and rate limiting with the concrete recovery action ('a 429 response carries retry_after_s, wait that long'). It also explains how to interpret the gated state and diagnose.tell_user.

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 with the action and the cost reassurance, and nearly every clause carries information an agent needs. However, it is delivered as one dense ~120-word paragraph mixing purpose, routing logic, auth, rate limits and diagnosis, which would scan better broken into discrete statements.

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 documented exhaustively, yet the description goes further and tells the agent how to read the important fields (workers_available, gated, gate) and how to relay diagnose.tell_user to the user. Nothing an agent needs to call this correctly is missing.

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 tool takes zero parameters, so per the rubric the baseline is 4. There is no parameter surface for the description to clarify, and it correctly spends its words on return-value interpretation instead.

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 scope: 'Check the connection and the service before rendering', then enumerates exactly what is reported (server URL, GPU worker health, queue length, expected wait, key usage). It is clearly a service-level diagnostic rather than a job-level one, but it never names the adjacent sibling render_status, so an agent must infer the boundary with that tool.

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?

Gives explicit triggering conditions ('before the first render', 'when renders seem stuck') plus a decision rule ('to decide whether to route a render here'). It also names the alternative path implicitly by explaining that workers_available > 0 vs gated determines whether a preview is worthwhile. This is textbook when-to-use guidance.

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