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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=false and openWorldHint=false, so safety is covered. The description adds only that summarization runs on "the platform AI" and the PDF pre-step; it says nothing about credit consumption (a sibling credits_usage exists), latency, or what the response looks like, so it clears the lowered bar without excelling.

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?

Two sentences, zero waste, with the core purpose front-loaded and the routing hint second. Every clause earns its place.

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 read-only two-parameter tool this is close to sufficient, but with no output schema the agent has no idea what the tool returns (string summary? structured object?), and the input length ceiling and mode-driven output shape are never mentioned.

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 0% for the two parameters, so the description should carry more of the load. It does name the three mode values and says the text should be an excerpt or a pdf_extract_text result, which adds source guidance, but 'brief/bullets/tldr' merely repeats the enum and the 20–20000 character bounds go unexplained.

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 gives a specific verb and resource ("Summarize a text or document excerpt with the platform AI") and enumerates the three output styles, so an agent immediately knows what the tool produces. It does not explicitly distinguish itself from its closest sibling ai_translate, though the verb 'summarize' is fairly self-differentiating.

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 states an explicit trigger ("Use this when the user wants a document summarized") and provides a concrete chaining instruction to call pdf_extract_text first when only a PDF is available. It stops short of naming when NOT to use it or which tool handles translation/other transformations instead.

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