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

The annotations already mark the tool as read-only and open-world, so the safety-profile burden is covered. The description adds a valuable behavioral detail not in the schema: OCI registries do not support this tool's browsing, and the user must know the chart name and call a sibling instead. It does not cover pagination or error handling, but with the output schema present, those are less critical.

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?

The description is concise (3 sentences), front-loads the primary purpose, and packs in a usage example plus an exception with alternative routing. Every sentence earns its place; there is no fluff or repetition of the schema.

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 tool is a simple search/list with a required URL and two optional params, and it has an output schema; the description covers the main purpose, the keyword usage, and the critical OCI exception. The only minor missing piece is clear guidance on what happens when an OCI URL is provided directly to this tool (e.g., error vs. skipped results), but that is not central to correct invocation. Overall, the definition is complete enough for normal use.

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?

All 3 parameters have descriptions in the schema (100% coverage), so the baseline is 3. The description adds beyond that with a concrete example of the keyword filter ('keyword=postgres'), which illustrates that it's a substring match. It also color how repository_url behaves differently when it's an OCI URL, meaning the rich parameter semantics are more than schema-alone provides.

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?

The description clearly states 'List or search charts in a Helm repository' with a specific verb and resource, and the keyword example makes the search behavior concrete. The OCI note further differentiates it from the get_versions/get_values siblings, so an agent can immediately tell this is a repository-level listing tool rather than a chart-specific retrieval tool.

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?

The description explicitly says when NOT to use the tool (OCI registries do not support this) and provides a direct alternative ('call get_versions or get_values directly'). It also gives the general usage context (provide repository_url, optionally filter by keyword). This is a clear when-to-use and when-not-to-use pattern.

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