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

Beyond the readOnly/idempotent annotations, the description discloses concrete behavior: it 'Returns ranked candidates with confidence and a decoded preview', auto-decodes up to 8 nested layers with a 60% confidence threshold, and explicitly states its limitation with keyed encryption. This gives an agent a clear model of what will happen when the tool is invoked.

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 three dense sentences: core purpose, behavioral details, and a clear limitation plus source. Every sentence adds information, and the most important action verb ('Identify') is front-loaded. There is no filler or duplication of schema content.

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 tool with a rich output schema, the description covers the input type, supported format families, the ranked/confidence/preview return behavior, the auto-decode loop and its stopping condition, and the keyed-encryption limitation. The source URL adds provenance. Nothing essential is missing for an agent to decide whether and how to call this tool.

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?

The input schema already describes the single parameter as 'The unknown text to identify and decode', and the description's reference to 'a piece of text' essentially restates that. With 100% schema description coverage, the baseline of 3 is appropriate; the description adds no further semantic detail such as length limits, character set, or example formats.

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 opens with a specific verb and resource: 'Identify what encoding or classical cipher a piece of text probably is' and enumerates concrete formats (Base64, Base32, hex, Morse, Caesar/ROT-N, etc.). It also says it 'auto-decodes nested layers', which clearly ties the name to an actionable, distinct function. This differentiates it from sibling tools by focusing on identification and automatic decoding rather than single-format conversion.

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 makes the primary use case explicit: provide unknown text and get an identification and decode. It also gives a clear when-not: 'Cannot break keyed encryption such as AES'. However, it does not name alternative tools for when the encoding is already known, relying instead on the sibling list, so it stops short of full routing guidance.

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