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

No annotations are provided, so the description carries the full burden. It usefully discloses the sign convention for shifting (positive delays, negative advances) and the cost (1 credit per call), but says nothing about output format, error behavior, or the size ceiling.

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 front-loaded sentence carries the whole contract, with the credit cost appended briefly. No filler or repetition of schema facts.

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 stateless 3-parameter transform with no annotations and no output schema, the core operation is covered, but the description omits what is returned (converted subtitle text), the default of shift_seconds, and the input length limit, all of which an agent would benefit from knowing.

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 0%, so the description has to compensate. It does: it explains that the conversion target is a subtitle format (SRT/WebVTT) and gives the semantic meaning and direction convention of shift_seconds, which the bare schema does not.

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 states a specific verb and resource ('Convert subtitle text between SRT and WebVTT') plus a second operation ('shift all timings by an offset'). The named formats make the scope unambiguous, though it never explicitly distinguishes itself from the broader convert_media/convert_data siblings.

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 when-to-use guidance and no alternatives named. An agent gets no help deciding between this and add_captions, transcribe_media, or timecode_calculator, nor any prerequisite or exclusion conditions.

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