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

With no annotations provided, the description carries the disclosure burden. It accurately describes the calculation behavior, mentions the configurable WPM with a default, and lists the output components (word/char counts, minutes, mm:ss). It doesn't disclose the exact return format or edge-case handling, but for a pure calculation tool this is sufficient.

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 description is a single, well-structured sentence. It front-loads the action verb, specifies the resource, and enumerates the key outputs. No redundant or filler language.

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 simple tool with 2 parameters and no output schema, the description is nearly complete. It covers the input (text, optional WPM), the operation (estimate reading time), and the expected outputs (word/char counts, minutes, mm:ss). A minor gap is the lack of explicit return format, but the listed outputs give a clear picture.

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 the schema already documents both parameters and their defaults. The description adds a bit of context by referring to 'a blob of text' and 'given or default WPM,' but does not fundamentally expand on the schema. Baseline of 3 applies because the schema carries the parameter meaning.

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 clearly identifies the tool's purpose: 'Estimate reading time for a blob of text.' It specifies the resource ('a blob of text') and the outputs (word/char counts, minutes, and mm:ss), which distinguishes it from sibling text utilities like word_freq or diff_text.

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 provides clear context for when to use the tool: whenever reading time estimation for text is needed. It implies a straightforward use case without exclusions. It doesn't explicitly name alternatives, but the tool's unique functionality among siblings makes the usage context obvious.

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