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

Annotations already cover readOnlyHint and openWorldHint, yet the description adds substantial behavioral detail: default trending, limit=20/100 cap, next_cursor continuation, cursor being ignored for breaking market-mover rows and mentions search results, source_kind inspection, and upstream error on empty feeds. This goes well beyond the safety profile in the 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?

Four front-loaded sentences with minimal waste; defaults and cursor rules are stated before the routing guidance. Slightly dense but every sentence carries useful information.

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 an output schema present, return values need not be explained, and the description covers defaults, pagination behavior, feed-type distinctions, error behavior, and sibling routing. Nothing an agent needs to call this correctly 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?

Schema coverage is 100%, so the baseline is 3, but the description adds real meaning: feed defaults to trending, limit is capped at 100, and cursor semantics differ by feed kind. This clarifies non-obvious interactions the schema alone does not capture.

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 verb ('Fetch') and resource ('normalized public Polymarket homepage feed rows'), and distinguishes itself from siblings by naming polymarket_markets for structured browsing and polymarket_event_detail for a single event. An agent can identify the tool's scope without opening another 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?

Names concrete alternatives (polymarket_markets, polymarket_event_detail) and the conditions selecting them, plus explains cursor applicability per feed type. It stops short of a full when-not narrative for this feed vs other Polymarket discovery tools, but the routing guidance is explicit and actionable.

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