One Globe and Mail article's public metadata and full body paragraphs from a canonical article URL. Subscriber-only stories return a permission error instead of a truncated or fabricated body.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| data | Yes | The tool result payload (shape varies per tool; see each tool's docs resource). |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely non-obvious behavior: subscriber-only stories yield a permission error rather than a truncated or fabricated body, which tells the agent how to interpret failure. Rate limits and exact auth requirements are not stated.
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, purpose front-loaded, with the failure-mode caveat second. No filler, though the opening sentence is a slightly dense noun phrase rather than a verb-first statement.
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 no explanation. The description covers the resource, the input constraint, and the notable error case, leaving only minor gaps around URL format and any pagination/truncation of very long articles.
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% and the sole parameter is an undocumented 'url' string. The description compensates partially by specifying that it must be a 'canonical article URL', a real constraint beyond the bare schema, but gives no format example or guidance for non-canonical URLs.
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 (one Globe and Mail article) and precisely what it returns: public metadata plus full body paragraphs. It is clearly the article-level fetch within the globeandmail_* family (author, headlines, news, sections), though it never names those siblings explicitly.
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 implied rather than stated: 'from a canonical article URL' signals that the caller must already have an article URL, which routes from headlines/news, but there is no explicit when-to-use or when-not-to-use guidance and no named alternative.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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