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

Annotations already declare readOnlyHint=true, and the description adds meaningful behavioral detail: the exact return shape, the source enum, optional fields, and the null/204 behavior when no FINANCE.md exists. This goes well beyond what annotations convey.

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 front-loaded with the core action and usage directive, then efficiently covers the spec link, return shape, and null case. Every sentence serves a purpose; no filler or redundancy is present.

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 simple read-only tool with one parameter, the description is complete: it defines what the resource is, when to call it, what it returns, and the missing-document case. The lack of an output schema is compensated by the explicit return field listing.

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 coverage is 100% and the model_id parameter is already well documented in the input schema, including UUID format and key-scope behavior. The description adds no additional parameter-level meaning, so the baseline of 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?

The description opens with 'Read the FINANCE.md attached to a model', a specific verb+resource combination, and clarifies the document's role as the financial conventions standard. It is clearly differentiated from siblings like layerz_set_finance_md and layerz_get_custom_instructions.

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 gives explicit usage context: 'Call this FIRST when starting to work on a model' and states that every other tool result must be interpreted under these conventions. It does not explicitly name alternatives or when-not-to-use conditions, but the priority instruction is strong and clear.

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