build_model

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

Annotations indicate readOnlyHint=false and destructiveHint=false, and the description adds critical behavioral details: atomicity, error reporting (names failing stage and index), default sync and validation, and response doubling as inspection. No contradictions with annotations.

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 well-structured sentences: purpose, error behavior, and defaults. No fluff, front-loaded with the primary action. Every sentence 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?

Given the tool's complexity (10 parameters, nested objects) and missing output schema, the description covers core aspects (purpose, atomicity, defaults). However, it does not describe the response format (since no output schema), which could help the agent. Still, it is sufficient for invocation decisions.

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?

With 100% schema description coverage, the baseline is 3, but the description adds essential context: the order of application (stocks first, then auxs, etc.) and the default behaviors for sync_connectors and validate. This significantly enriches understanding beyond the schema.

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 clearly states the tool's purpose: 'Create and populate a model in one call' and enumerates the components (sim specs, stocks, auxiliaries, flows, connectors, modules). This distinguishes it from sibling tools that add individual elements (e.g., add_stock, add_flow).

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 description explains the 'All-or-nothing' atomicity and that connector sync and validation run by default, guiding when to use this batch operation. However, it does not explicitly contrast with alternative single-step tools or mention scenarios where partial success is needed.

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