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

Annotations only declare the safe read-only/idempotent profile, but the description adds real behavioral detail: each puzzle gets its own substitution key in which no letter stands for itself, only A-Z are enciphered while accented letters and other alphabets stay as written, the output is a PDF ending in an answer key, and puzzles[] takes precedence over text. These are non-obvious output characteristics an agent could not infer from the annotations.

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 trigger, conversion rule, and exclusion are front-loaded and easy to scan in a single dense paragraph. The parenthetical keyword list ('cryptogram maker, cryptoquote puzzles, cryptogram puzzles printable with answers, large print cryptograms') is search-oriented filler that adds length without adding instruction.

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 an 11-parameter optional-everything generator with an output schema, the description covers the decision that matters most (puzzles[] vs text), the output format (PDF with answer key), typography options, and the fallback behavior when no quotes are supplied. Nothing an agent needs in order to call it correctly is missing.

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 baseline is 3; the description still adds value by declaring puzzles[] the preferred input and text only a fallback, and by explaining that hints override difficulty. It loses a point because the stated 'Up to 30' puzzles and 'up to 1,000 characters are used' conflict with the schema's maxItems of 500 and maxLength of 2000, which could mislead an agent about the real limits.

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 artifact ('generate printable cryptogram puzzles') plus the input source ('their own quotes or phrases'), and explicitly names the sibling it is not ('Does not make symbol ciphers or solve puzzles (use solve_cryptogram)'). The parenthetical keyword variants clarify intent without obscuring the core action.

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?

Opens with an explicit trigger ('Use this when the user wants printable cryptogram puzzles'), gives a fallback rule ('If the user gives no quotes, pick suitable public-domain quotes first'), and routes the excluded case to solve_cryptogram. When-to-use, when-not-to-use, and the alternative are all present.

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