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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds useful behavioral context beyond that: the result is a side-by-side rendering across five named styles, each with stroke playback. It does not discuss output format details, but an output schema exists to carry those.

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?

A single well-formed sentence that front-loads the core action and enumerates the styles compactly. There is no redundant or filler wording, and every clause carries information.

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 read-only tool with one optional, fully documented parameter and an existing output schema, the description supplies enough context to call it correctly. Minor gaps remain around what exactly playback looks like, but the output schema and annotations fill the rest.

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 schema already documents the 12-character limit, pattern, and default of "Aa". The description restates 'one letter or a short word' without adding syntax or format details beyond the schema, so the baseline of 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?

The description states a concrete verb and resource ('Shows one letter or a short word in all five cursive styles side by side') and enumerates the five styles, so the agent knows exactly what the tool produces. It does not explicitly name how it differs from siblings like show_letter or show_alphabet, but 'all five styles side by side' implicitly distinguishes it as the comparison view.

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 comparison framing implies when to reach for it (to contrast styles for a given letter), but there is no explicit when-to-use or when-not guidance and no sibling is named as an alternative. The agent must infer that show_letter is for a single style while this is for the multi-style view.

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