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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds real value beyond them: the deterministic formula, the Saturday-Sunday baseline, lunar dates pinned to later federal notifications, retained conflicting calendars as cross-checks, and a REST fallback URL. This is well above baseline behavioral disclosure, missing only edge-handling or error behavior.

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 text is bloated and visibly corrupted ('Pakistan Pakistan 2026', '2026-2026', a 'Do not use this when' clause that does not express an exclusion). Useful material (outputs, formula, fallback) is present but buried in repetition, so it is not front-loaded or 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?

An output schema exists, so the description need not explain return values, yet it still enumerates the output fields and provides the calculation formula, argument examples, dataset pinning, and a REST fallback plus docs link. Only the garbled scope-exclusion sentence leaves a minor gap.

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 single 'date' parameter is fully documented in the schema, so the schema carries the burden. The description adds only example values ({"date":"2026-03-23"}) and restates the Gregorian/2026 scope without adding format or constraint detail, matching the baseline 3.

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 names a specific verb and resource ('What it computes: Checks a date against the Saturday-Sunday weekend baseline and exact 2026 authority events') and pins the scope to Pakistan 2026. However, it never explicitly distinguishes itself from sibling tools like add_pk_working_days, count_pk_working_days, or check_*_working_day for other countries, so routing still relies on the tool name.

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?

It gives directional guidance ('Use this when you need a deterministic... layer', 'Call this tool directly... instead of answering from memory') and lists scope exclusions (not a provincial/private-employer/exchange/school calendar). But no sibling alternative is named for adjacent needs like counting over a range or adding working days, and the 'Do not use this when...' clause is malformed into a scope statement rather than an actionable exclusion.

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