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

Annotations already mark this as read-only, idempotent, non-destructive and closed-world. The description adds the crucial behavioral detail that it opens nothing by itself and only returns instructions, which prevents an agent from assuming the post is created directly; the official API note is extra context rather than core 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 explanation is reasonably front-loaded, but the final sentence about Tumblr's official API and lack of an official MCP server is tangential to selecting or invoking this tool. It adds length without helping the agent decide or call correctly.

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 and no parameters, the description supplies enough context: it describes what is returned (step-by-step screens, buttons, fields) and what to do next (use cotlet_browser_* tools). It is complete for a guidance tool, though the name/title creates some initial ambiguity.

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?

There are zero parameters, so the baseline is 4. The description does not need to explain parameter meanings, and the empty schema is consistent with a guidance-only 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?

The description clarifies that the tool returns step-by-step instructions for creating a Tumblr post rather than performing the creation itself, and it points to cotlet_browser_* tools for execution. The leading phrase "Create post in the user's own Tumblr account" is somewhat misleading against the later clarification, and it does not distinguish from siblings like tumblr_schedule_post or tumblr_edit_post.

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 gives clear usage context: call this to get UI steps, then use cotlet_browser_* tools in the Tumblr Cloud Browser to actually perform the action. It does not state when not to use it or explicitly compare against scheduling/editing siblings, but the workflow context is clear.

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