get_user_id

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

With no annotations, the description carries the burden and does disclose the key behavior: it reads configuration from the server environment rather than from user input, and it spells out the return shape and path semantics ('users/<id>' or 'groups/<id>'). It stops short of stating failure behavior when no library is configured or whether credentials/scopes affect the result, which keeps it off a 5.

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 sentences: what it returns first, then what to do with the value, then when to skip it. No filler, and the most actionable element (library_path) is front-loaded in the opening sentence.

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?

There is no output schema, so the description must explain the return values — and it enumerates all four fields plus the path format. For a zero-parameter lookup tool, an agent has everything needed to decide whether to call it and how to use the result.

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 takes zero parameters, so the baseline of 4 applies and there are no parameter semantics to explain. The description correctly spends no words on inputs and instead redirects that space to output field meaning and downstream consumption.

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 — returns the Zotero library configured in the server environment — and enumerates exactly which fields come back (user_id, library_type, library_id, library_path) with the path format shown. It also indirectly corrects the narrow-sounding name by clarifying the scope is the whole library config, and names inject_citations as the sibling that makes it unnecessary.

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?

Gives explicit positive guidance ('Pass library_path to the zotero-mcp-integrations skill script (inject.js) to generate Zotero field code URIs') and explicit negative guidance ('Not needed when using the inject_citations MCP tool, which reads the library internally'). The when/when-not split and the named alternative leave nothing to inference.

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