PDF: read an attached file

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

Annotations already declare readOnlyHint=true, and the description confirms the read-only, decoded-to-text nature of the operation. It adds the useful detail that the content is decoded as text and that only file-attachment xrefs qualify, but says nothing about failure behavior for invalid/non-file xrefs.

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 short sentences, front-loaded with the action and followed by the precise semantic constraint. No filler, though the second sentence is somewhat dense/jargon-laden.

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-value explanation is unnecessary. For a two-parameter read tool the description covers the key linkage to `annotations`, but the undocumented `path` parameter leaves a gap in what an agent needs to call it correctly.

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 description coverage is 0%, so the description carries the burden. It explains the required `xref` well (an xref from `annotations` carrying a `file` field), but the optional `path` parameter is completely unexplained in both schema and description.

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 verb and resource ('Read an attached file back as text') and pins the scope to file-attachment annotations, which separates it from the generic `annotations` sibling. It does not explicitly contrast with the reverse operation `attach_file`, so it stops short of a 5.

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: it tells the agent the xref must come from `annotations` with a `file` field, which is a de facto precondition. There is no explicit when-not guidance or named alternative for adding attachments.

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