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 two useful behaviors: automatic millisecond detection and rejection of invalid dates with clear errors, plus per-call pricing. However it omits timezone assumptions for the to_timestamp direction and what the returned value looks like, leaving notable behavioral gaps for a no-annotation tool.

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?

Two compact sentences front-load the core conversion behavior and the ms-detection/error-handling facts; the appended pricing note is separated by a dash and doesn't bury the primary purpose. Slightly dense given three distinct ideas packed into two sentences.

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?

No output schema and no annotations exist, so the description should fully cover input and return semantics. It covers the value formats and error behavior but never specifies the return type for either direction (e.g., epoch seconds vs. ISO string), which is a real gap for an agent invoking it 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 100% and the enum on 'op' documents direction, so the schema already handles the parameters. The description adds only marginal meaning ('Millisecond timestamps are detected automatically', 'invalid dates are rejected') tied to the value parameter, so the baseline 3 is appropriate.

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 (convert) and resource (Unix epoch timestamps / ISO-UTC dates) with bidirectional scope made explicit by 'and back'. This clearly separates it from nearby siblings like calculators_date_difference_calculator and dev_natural_date.

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 establishes context (timestamp<->date conversion, automatic millisecond detection) but never states when to prefer this tool over alternatives such as dev_natural_date or calculators_date_difference_calculator, nor any exclusion cases. Usage is only implied by the tool's name and description.

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