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

With no annotations, the description carries the full burden, and it does disclose one genuinely useful behavioral rule: payday is suggested as the last working day or the 25th rolled back. It still omits whether the operation is read-only, how region affects bank-holiday results, and what failure looks like without a valid subscriber token. Partial disclosure of behavior beyond the schema.

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?

A single compact sentence that front-loads the month scope and enumerates outputs efficiently. The only wasted token is the unexplained 'PRO.' marker, which costs clarity rather than length.

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?

There is no output schema, so the description must convey return values; it names the categories but leaves 'deadlines' ambiguous (tax? user-supplied? statutory?) and says nothing about the shape of payday suggestions or holiday output. For a compound, three-parameter tool with no annotations, this is adequate but thin.

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%, so month format, the region enum values, and the access_token source are all documented in the schema. The description adds nothing about any of the three parameters — no mention of region affecting holidays or of the token's role. Baseline 3 is appropriate since the schema does the work.

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 lists the concrete outputs (working days count, bank holidays, payday suggestions, deadlines) for a given month, which gives a reasonably clear sense of the resource. However, it never states a verb or that this is an aggregate/month-summary tool, and it does not distinguish itself from siblings like working_days, next_bank_holidays, or tax_deadlines that appear to overlap. The cryptic 'PRO.' prefix adds no clarity.

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 guidance on when to pick this tool over working_days, next_bank_holidays, tax_deadlines, or due_date, which cover adjacent ground. The 'PRO' marker hints at a subscription gate but is never explained, and there is no mention of when the access_token is required or what happens without it.

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