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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description's 'Read-only' adds nothing beyond the annotation; its only incremental value is explaining the possible sources of the fiscal-year start. No permission, rate-limit, or error behavior is disclosed.

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?

One compact sentence, front-loaded with the verb and the returned value. The trailing 'Read-only' is redundant with the annotations and slightly wastes space, but the text is otherwise tight.

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?

With an output schema present, the description needn't explain return values, and with annotations covering safety it needn't cover read-only behavior either. For a simple single-parameter settings getter, the definition is essentially complete; only a when-to-use cue 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?

Schema description coverage is 100% and the single companyId parameter is fully documented in the schema, so the baseline is 3. The description adds no syntax or meaning beyond the schema, but none is needed for a single documented UUID parameter.

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 ('returns') and resource (the company's fiscal-year start) plus the provenance of that value (person setting, EIN closing month, or default January). This clearly distinguishes it from the accounting reporting siblings. It stops short of explicitly naming a sibling it differs from, so not a 5.

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?

There is no statement of when to call this versus alternatives, no prerequisites, and no exclusions. The only hint ('Read-only') is a restatement of the annotation rather than usage guidance. An agent must infer usage from the name alone.

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