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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and reach are covered. The description adds only the 'public' qualifier (implying no auth for non-public content) and that body paragraphs are returned; it says nothing about rate limits, failures, or pagination. Comparable to the calibration case where annotations carry the behavioral burden.

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: the primary action is front-loaded and the routing alternatives follow immediately. 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?

An output schema exists so return values need not be described, annotations cover the safety profile, and the single parameter is fully documented in the schema. Purpose, routing, and input source are all present, leaving nothing an agent needs to call it correctly.

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% with a single url parameter, so the schema already documents the input fully. The description's phrase 'from its canonical url' merely restates the schema's 'Canonical Dawn article URL' with no added format or constraint detail, making the baseline 3 correct.

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) plus resource (public Dawn article details and body paragraphs) and names the input source (canonical url). It is clearly distinguishable from dawn_headlines, dawn_news, and dawn_sections, which are named as different tools.

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?

Explicitly routes the agent: use dawn_headlines to discover links, dawn_news for the general feed, dawn_sections to browse sections. When-to-use-this vs alternatives is fully spelled out with no inference required.

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