jina_read

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

With no annotations, the description carries the full burden and does add useful behavior: it discloses the auth model ("free tier, no key") and the output format (clean markdown). It omits rate limits, timeouts, JS-rendering limits, and error behavior for failed fetches, which for a web-fetch tool are notable gaps.

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 short sentences with zero filler, front-loading the core action and mechanism before the fallback clarification. 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 single-parameter fetcher with no output schema and no annotations, the description covers the essentials an agent needs: what it returns (markdown), how it authenticates (no key), and its role (fallback). Only failure-mode and rate-limit behavior are left unaddressed.

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 0%, so the description must compensate, and it only loosely characterizes the single required parameter as "any URL." This clarifies that arbitrary web URLs are accepted, but adds no format, scheme, or validation detail beyond the bare schema string type.

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 and resource ("Fetch any URL as clean markdown via Jina Reader"), making the tool's function immediately legible. The "any URL" scope implicitly contrasts with the domain-specific sibling APIs (sec_edgar, fred_series, etc.), but no sibling is named, so differentiation is inferential rather than explicit.

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?

"Extraction fallback" signals this is a secondary/generic extraction path rather than a primary data source, which implies when to reach for it. However, it never states the condition that triggers fallback, nor names any alternative to prefer first, leaving usage guidance implied rather than spelled out.

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