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

Annotations already mark readOnlyHint=true, and the description reinforces this by explicitly stating the tool only reports and does not convert or rewrite the file. It also adds useful behavioral context about what kinds of files and encoding issues it addresses. The description aligns with and slightly extends the annotation-provided safety profile.

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 compact and front-loaded, starting with a clear one-line summary followed by a practical use case and an explicit scope limitation. Every sentence earns its place, and the category tag is unobtrusively appended.

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, read-only detector tool, the description covers the trigger scenario, supported encodings, input file types, and the boundary of what it does not do. No output schema exists, but the description's 'reports the encoding only' sufficiently conveys the outcome. Nothing critical 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?

The single parameter 'file' is already fully documented in the schema with type, format, and accepted extensions (TXT, HTML, CSV, XML), so schema coverage is 100%. The description adds no new parameter-specific semantics beyond listing example encodings, which is marginal value. Baseline 3 is appropriate.

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 clearly identifies the specific action 'Detect the character encoding' and the resource 'text or HTML file.' It also distinguishes itself from conversion tools by stating 'It REPORTS the encoding only — it does not convert or rewrite the file,' making its purpose unmistakable among the large sibling set.

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?

It provides an explicit trigger condition: 'Use when accented letters, apostrophes or quotation marks arrive as garbled symbols.' It also clarifies what it does not do, so an agent knows not to use it for conversion or rewriting. However, it does not name specific alternative tools or state when not to use it beyond the conversion exclusion.

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