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

Annotations indicate readOnlyHint=false and destructiveHint=false, meaning the tool is a non-destructive write operation. The description adds that it creates a resource and returns its UUID, and notes API key restrictions—useful context beyond annotations. However, it doesn't detail behavior like validation side effects or whether templates are required, but given the annotations and the clear creation semantics, a 3 is appropriate.

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?

The description is moderately long but well-structured: a clear opening sentence, then a valuable but detailed glyph guidance section. The glyph guidance is somewhat verbose but earns its place given the parameter's complexity. The key usage constraints are front-loaded, and the API key limitation is at the end. Overall efficient, but the glyph list could be more concise.

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?

The tool has multiple optional parameters (subtitle, timelines, template_id) and no output schema. The description explains the glyph parameter thoroughly and mentions the UUID return, but does not elaborate on timelines structure or template_id usage. However, given that nested objects (timelines) are described in the schema and the required name is simple, the description covers the most critical decision-making context, making it largely complete. A minor gap remains for template_id, but overall the tool can be called correctly.

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 low at 20% (only the glyph parameter has a description). The description compensates substantially by explaining the naming conventions and providing domain-specific examples for glyph, which adds semantic meaning beyond the schema. It also hints at the role of name and other parameters, though not each in detail. This elevates the score above the baseline.

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 creates a new financial model and returns its UUID. It is distinct from siblings like layerz_get_model, layerz_patch, or layerz_build_from_blueprint, which involve retrieval or modification. The description makes the purpose unambiguous.

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 provides explicit guidance on when to use this tool, including the type of model to create, suggested glyph choices by business domain, and a clear prevention: 'Not available for model-scoped or read-only API keys.' This exceeds typical usage guidance and directly helps the agent select the tool over alternatives like layerz_patch or layerz_build_from_blueprint.

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