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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds genuinely useful output-shape context (full markdown, code listings preserved verbatim), but says nothing about failure on a non-canonical or unreachable URL, truncation on long articles, or whether content is cached.

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?

The core sentence is front-loaded and efficient, but the trailing "The same as fetch, as plain text" partially restates the title's "(plain text)" while adding ambiguity rather than information. A rewrite naming the actual difference from fetch would use the same space far better.

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 read tool with no output schema, the description covers the essential contract: input form, output format, and fidelity of code blocks. Only edge-case behavior on bad URLs or oversized pages is left unstated.

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% for the single url parameter, so the schema already documents it. The description contributes only the concrete example plus the word "canonical," which hints at the accepted URL form but does not clarify what happens with redirects or non-canonical variants — baseline 3 is appropriate.

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?

"Return the full markdown of one article by its canonical URL" gives a specific verb and resource, and the example URL pins down the expected input format. However, the closing line "The same as fetch, as plain text" leaves the distinction from the sibling fetch tool ambiguous rather than crisp.

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?

There is no stated condition for choosing this over fetch — it only says it is "the same as fetch, as plain text," which conflates the two rather than separating them. No prerequisites, no when-not-to-use, and no mention of what fetch returns that this does not.

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