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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint false, and openWorldHint false, so the safety profile was covered. The description adds real context beyond them: nothing is executed, the return value is a screen-by-screen guide, and the actual mutation happens through the browser tools. The closing OAuth/API note is extraneous to behavior.

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 well front-loaded, but the description also includes marketing framing ("from ChatGPT, Claude or any AI agent") and a dated note that Inoreader has no official MCP server. Neither helps the agent call this tool correctly, so the text is longer than its job requires.

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 zero-parameter tool with no output schema, the description does explain what comes back (a step-by-step guide) and who performs the real work. It is incomplete on target selection: nothing says which items get marked read, or whether the guide depends on browser context. That gap matters for an agent deciding whether to call this at all.

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?

The tool has zero parameters, so the baseline is 4. However, the definition never addresses the target problem: with no parameters, the tool cannot identify which article to mark read. That omission keeps the score at 3 rather than 4, because an agent cannot tell from the schema or the description how the target is scoped.

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?

The description states the resource and the real behavior: it produces a step-by-step how-to for marking items read, and explicitly says it "opens nothing by itself." That correction is important because the name inoreader_mark_as_read reads like an action tool. It is not differentiated from siblings like inoreader_star_article or inoreader_tag_article, which are structurally similar instruction 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?

It names the follow-up path clearly: use the cotlet_browser_* tools in the user's Inoreader Cloud Browser after reading the returned steps. It does not say when to prefer this over other read/star/tag tools, and it gives no exclusion criteria.

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