index_materials

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

Annotations already declare readOnlyHint=false, openWorldHint=true and idempotentHint=false, so the agent knows this writes and is not idempotent. The description adds the real side effect (text index creation) and the batch ceiling, but says nothing about re-indexing an already-indexed file, processing time, or whether the job is synchronous. With annotations carrying the safety profile, this is adequate but not rich.

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 short sentences, action first, then the batch constraint, then the follow-up step. No filler and nothing buried.

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 single-parameter batch tool with no output schema, the essentials (what it does, batch cap, next step) are covered, but the agent still doesn't know what a call returns, whether indexing is asynchronous, or how failures on individual IDs are surfaced.

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 single required 'ids' parameter has 0% schema description coverage, and the description only echoes the batch size (max 10) already enforced by maxItems. It never explains the accepted ID forms (ubfile:/resource:/folder:/file: hex), which the pattern encodes but the agent gets no prose explanation for.

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 compound action: download the selected materials AND build a text index, which distinguishes it from pure-download siblings like download_material/download_materials. It does not explicitly say how it differs from those siblings, so the agent must infer that indexing is the added value.

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 a clear workflow condition: after completion, use search_materials to search. It also constrains the batch to 10 files per call. However, it never states when to prefer this over download_materials or download_material, so alternatives are not addressed.

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