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

Annotations already establish read-only and closed-world behavior, but the description adds genuinely new traits: deterministic output via `seed` and a renderability caveat that heavy text may be trimmed by some apps. The only gap is it doesn't clarify the response shape of the renderability estimate beyond that warning.

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?

Three tight sentences with no filler: purpose first, then parameter selection, then determinism and the output caveat. Every clause carries actionable 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 six-parameter, read-only transform tool with no output schema and sparse schema descriptions, this is nearly complete: it covers the presets, exact channels, seed behavior and output caveats. Missing only the input length limit and a per-channel explanation.

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 only 17%, so the description carries most of the burden — and it does, explaining the light/medium/heavy preset, the 0-100 ranges for `above`/`mid`/`below`, and the repeatability role of `seed`. It omits the 500-character cap on `text` and doesn't distinguish the three positional channels beyond the opening sentence.

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 and resource — turn text into zalgo/glitch text with combining marks above, through and below each letter — which is concrete and unambiguous. It does not explicitly contrast with the sibling `fancy_text`, so an agent must infer the difference (glitch/zalgo vs. stylized fonts) from the wording alone.

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 explains how to choose between the preset `intensity` and exact `above`/`mid`/`below` values, which is useful invocation guidance. However, it offers no guidance on when to pick this tool over `fancy_text`, and no exclusions or prerequisites are stated.

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