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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description's job is to add context beyond that. It adds that the operation uses AI and returns a summary, which is minimal but consistent. It does not disclose potential cost, latency, or failure modes, but the safety profile is covered by 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 description is two sentences long, front-loaded with the core action and source types, and avoids redundancy with the schema. It is efficient, though the second sentence could be integrated to save a line.

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?

With no output schema, the description must clarify what is returned; it says 'Returns the summary' but not the format or structure. It covers the input constraints well, but lacks details on output format, error handling, or edge cases. For a moderately complex tool with 5 optional parameters, this is adequate but not rich.

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 description coverage is 100%, so parameters are fully documented. The description adds the constraint that exactly one source must be provided, which is useful guidance beyond the schema. However, it does not clarify parameter formats (e.g., base64 encoding) beyond what the schema already states.

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 states a clear verb ('Summarize') and specifies the resource types (web page, PDF, Office file, raw text), distinguishing it from sibling tools like extract_text or extract_pdf_text by focusing on summarization via AI. It is unambiguous and specific.

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 explicitly states that exactly one source must be provided and lists the four source parameter types. However, it does not name alternative tools or explicitly state when not to use it, though the purpose is distinct enough that an agent can infer appropriate usage.

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