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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds that the response is descriptive metadata about lanes and mirrored datasets, which is useful context, but says nothing about size, freshness, or whether lanes differ per server configuration.

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?

A single front-loaded sentence with no filler; the key fact (which lanes this server supports) comes first. The trailing clause about mirrored datasets is dense but carries real information, so nothing is clearly wasted.

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?

This is a trivial no-parameter read tool with an output schema, so the description needn't explain return values. Still, it could be clearer that the result enumerates valid sourceTypes values for search_medical and whether search_papers shares those lanes, which matters for routing between siblings.

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 there is nothing for the description to disambiguate and the baseline of 4 applies. It does mention sourceTypes, but that parameter belongs to search_medical rather than this 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?

States a concrete job: describe the corpus the server searches, specifically the source lanes accepted by search_medical's sourceTypes and the mirrored datasets beneath each. That is more specific than the title's generic 'List the indexed datasets' and ties the tool to a named sibling, though the verb 'describe' vs. 'list' leaves the exact output shape slightly fuzzy.

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: by naming search_medical's sourceTypes, it hints you call this before search_medical to learn valid lane values. There is no explicit 'use this when' or any exclusion against fetch_source_record or search_papers, so the agent must infer the ordering.

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