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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the bar is lower. The description adds real behavioral context beyond them: photo/video items often have empty bodies, and long stories are chunked so parts > 1 requires repeat calls.

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?

Three short sentences, front-loaded with the core behavior, then the coverage caveat and the pagination rule. No repetition of schema or annotation content.

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 carries the return-value burden and does so adequately (full body text plus a `parts` count driving re-calls), and covers the photo/video edge case. It stops short of naming other returned fields such as title or date, which would be a minor addition.

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 the operational meaning of `part` — the loop 'call again with part=2, 3, ...' when parts > 1 — which the schema alone does not convey. It also reinforces that the url should come from the sibling listing tools.

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?

Names a specific verb and resource ('Fetch one article page and return its full body text') and immediately qualifies the scope with pagination behavior, which cleanly separates it from the discovery siblings nw_search / nw_latest / nw_latest_all.

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?

States that it 'works for every source' and that the URL should come from the discovery tools, and gives an explicit follow-up rule for parts > 1. It does not spell out an exclusion against alternatives, but the position in the workflow (follow-up to search/latest) is clear.

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