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

With no annotations, the description carries the disclosure burden; 'Pure CPU, instant' usefully signals no network, no auth, and no side effects. It stops short of explicitly declaring read-only/deterministic behavior or describing the returned structure, which matters for the lookup-vs-table distinction.

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?

One front-loaded sentence with no filler; the output fields and the CPU-only trait come first. Brevity tips into under-specification rather than padding, but nothing is wasted.

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 simple single-parameter tool with no output schema, the enumeration of returned fields (character, decimal, hex, binary) covers most of what an agent needs. The unresolved question of how a required q selects between full-table and single-character lookup leaves a real gap.

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% and q is already documented as 'Character or code', so the schema does the heavy lifting and baseline 3 applies. The description weakly hints that a single character yields a lookup and something else yields a table, but never resolves the ambiguity for a required parameter.

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 resource and output shape: 'Return ASCII codes with character, decimal, hex and binary, or look up one character.' The verb+resource pairing makes the tool distinguishable from sibling converters like hex_dump or base_convert without opening the schema.

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 'or look up one character' clause implies two modes of use, but it never says which input triggers which mode, nor when to prefer this over neighbors such as emoji_list, html_entities, or hex_dump. Usage is inferable but not stated.

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