count_characters

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

The description is minimal and does not disclose behavioral details beyond the basic operation. Without annotations, the agent doesn't know if it counts all characters (including whitespace, newlines) or only visible characters. Edge cases like empty strings or special characters are not mentioned.

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 extremely concise with no wasted words. For such a simple tool, this is acceptable, though it could benefit from slightly more detail without becoming verbose.

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 straightforward counting tool with a single parameter and no output schema, the description is mostly adequate but lacks specifics about what constitutes a character. More detail on counting behavior would improve completeness, especially given similar sibling tools.

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% for the single parameter 'text', and the description adds the purpose of the parameter indirectly. However, the description does not add any information beyond what the schema already provides ('The text to analyze'). Baseline 3 is appropriate as no extra context is given.

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?

Description clearly states the tool counts characters in text, which is specific and directly matches the tool name. However, it doesn't differentiate from similar sibling tools like count_words or count_lines, leaving some ambiguity about what qualifies as a character (e.g., spaces, punctuation).

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?

No guidance is provided on when to use this tool versus similar counting tools. Given siblings like count_words and count_lines, the description lacks instructions on what makes this tool appropriate for character counting instead of word or line counting.

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