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

Annotations already declare readOnlyHint=true, so the description need not restate safety. It adds useful behavior context – bounded item text and note/highlight bodies, plus asset metadata carrying an MCP resource URI for original bytes – but does not discuss truncation semantics, pagination, or errors, and has an output schema available. A 3 is appropriate because it adds moderate context beyond structured fields.

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 concise sentences with no wasted words. The Boolean output in the provided reasoning cannot affect the score. The key context – that this reads a single object from a known list – is front-loaded.

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 simple two-parameter read tool, the definition covers the high-level purpose, bounded return content, and asset metadata URI. An output schema exists, so return values need not be explained. It leaves a minor gap around obtaining ref, but is otherwise complete enough to call 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?

The schema covers content_max_characters with a description, giving 50% coverage overall because ref has no schema description. The description does not explain what ref is or how to obtain it, so it fails to compensate for the undocumented ref. Baseline 3 is appropriate when about half the parameters are documented in the schema.

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?

Clearly states a specific verb and resource: read one library object returned by list_library_objects. Distinguishes fetching a single object from listing, searching, or bulk operations. Does not explicitly contrast with siblings like get_library_item, search_saved_item, or get_library_asset, so it falls 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?

Implies usage by saying the object was returned by list_library_objects, which suggests a follow-up lookup flow. However, it provides no explicit when-to-use vs alternatives, exclusions, or prerequisites, and there is no route to the many sibling tools that also retrieve library content.

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