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

Annotations already flag destructiveHint=true and openWorldHint=true, and the description usefully explains the source of that cost: 1 token per 50 grid cells, with a 40x40 grid emptying the bucket. It also discloses the refusal condition for non-continuous models. It does not explain failure behavior beyond that, keeping it short of a 5.

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?

Three sentences, front-loaded with purpose, then the constraint, then the cost. Dense but every clause carries information; the quoted example earns its place by anchoring the abstract grid concept.

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?

Covers what the tool does, what it returns, the input constraint, and the cost for an 8-parameter tool with no output schema. The only gap is not explaining what happens on failure or how refused models should be handled, but the core call semantics are complete.

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 already documents all 8 parameters including range format and bounds. The description adds conceptual framing (two rates varied together, run to the horizon) but no syntax or format detail beyond the schema, so the baseline 3 applies.

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: vary two transition rates over ranges, run each combination to the horizon, return the observable's final value as a grid. The concrete example ('which regime of arrivals × restock keeps the queue empty') makes the operation unambiguous and unlikely to be confused with siblings like sim_optimize or sim_scenario.

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 a clear use case and an explicit exclusion: 'Continuous reading: a model with a schedule or a gate is refused with the reason.' It does not name a sibling alternative to use instead when a model has a schedule or gate, so it stops short of full when/when-not/alternatives guidance.

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