postmd_upload_attachment

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

With no annotations, the description carries the behavioral disclosure burden. It discloses the required auth scope, allowed file types, and the returned data.url usage. It does not mention limits like file size or overwrite behavior, but the main side effects and prerequisites are covered.

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?

Three concise sentences front-load the purpose, then give the requirement, allowed types, and the next step. There is no filler or redundant restatement of the schema.

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 two-parameter upload tool with no annotations and no output schema, the description is strong: it covers auth, accepted types, how to use the response URL, and the logical next tool call. Nothing essential for a correct invocation is missing.

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 input schema already documents both parameters: filePath (path on the MCP server host, absolute preferred) and fileName (defaults to basename of filePath). The description adds the allowed-file-types constraint but does not add significant parameter-specific meaning beyond the schema, so the baseline of 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?

The opening sentence uses a specific verb ('Upload') with a clear resource ('an image or PDF') and purpose ('to reference from a document'). This distinguishes it from the sibling create/update tools, none of which target attachments.

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?

The description gives clear when-to-use context: uploading an image or PDF to be referenced from a Markdown document. It also states the prerequisite API key scope and the follow-up workflow using postmd_create_document, though it does not explicitly discuss when not to use this tool.

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