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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuine value by enumerating payload contents (facts, sources, call, full text), which tells an agent this is a heavy full-body response rather than a summary. It says nothing about error behavior for unknown slugs or response size, which matters for a full-text fetch.

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?

One short sentence with the key qualifier ('full') front-loaded and a compact parenthetical enumerating contents. No waste, though the parenthetical is doing param/return work rather than the main clause.

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 one-parameter, annotation-covered read tool with no output schema, the description gives enough to call it correctly and to predict roughly what comes back (full text plus structured facts and sources). Only the absence of any failure-mode or sibling-routing note keeps it below a 5.

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%: the single slug parameter is documented in the schema with a concrete example. The description adds no further meaning about slug format, derivability from URLs, or case sensitivity, so it sits at the baseline for a schema-complete tool.

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 resource and a specific retrieval mode: the 'full machine-readable article' as the 'JSON twin' of the rendered page. The word 'full' implicitly contrasts with the trimmed results of search_articles, but no sibling is named outright, so differentiation is left to inference.

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?

Usage is only implied: an agent can infer this is the fetch-by-slug step after discovering a slug elsewhere. There is no explicit when-to-use, no mention of search_articles as the discovery alternative, and no stated preconditions such as a missing or stale slug.

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