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

With no annotations, the description carries the full burden. It usefully discloses determinism ('Deterministic formulas') and a pricing model ($0.01/call, USDC, eip155:8453), but never states that it is a pure read-only computation or describes the return format, which matters given there is no output 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?

Front-loaded with the metric list, which is the most useful information. However the 'Use this when an agent needs to flesch reading-ease and grade level for any text' sentence is redundant with the opening and could be dropped.

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 single-parameter, no-output-schema tool, the description is nearly sufficient: it enumerates the returned metrics, which compensates for the missing output schema. Remaining gaps (read-only nature, return shape) are minor for a stateless calculator.

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?

Only one parameter ('text') with 100% schema coverage, so the schema already documents the input. The phrase 'a block of text' adds no format, size, or encoding detail beyond what the schema provides; baseline 3 applies.

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 (compute) and resource (readability metrics) and enumerates the exact outputs — Flesch Reading Ease, Flesch-Kincaid grade level, word/sentence/syllable stats. It is clearly distinguishable from near siblings like calculators_reading_time_calculator or dev_token_estimator, though it never names an alternative explicitly.

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 offers context ('useful for checking documentation, prompts and agent output clarity') and a when-to-use sentence, but that sentence largely restates the first one. There is no when-not guidance and no explicit routing to or away from sibling text tools.

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