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

The annotations already supply readOnlyHint, idempotentHint, and destructiveHint, which cover safety and side effects. The description adds that it's a text-query lookup, which is consistent and provides additional clarity about the operation without contradicting the annotations.

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 two sentences long, with no fluff. It front-loads the core action ('Search vault credentials by keyword') and then provides necessary context and differentiation. Every sentence earns its place.

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?

Given the output schema is present (likely a list of credentials), the description does not need to explain return values. It fully covers the tool's purpose and usage context, making it complete for an agent to decide to call it.

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 fully describes all three parameters (search, type, agentId) with their types and descriptions. The description does not add new semantic meaning beyond what's in the schema, but it reinforces the search behavior. Since schema coverage is 100%, a baseline score of 3 is appropriate.

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 the action (search), the resource (vault credentials), and the scope (across names and content). It explicitly differentiates from vault_credential_list by describing the access pattern, making it easy for an agent to distinguish it from siblings.

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 provides explicit guidance on when to use this tool: 'Use when you know part of the name, URL, or username but not the exact credential ID.' It also contrasts with list ('list is paginated browsing, search is text-query lookup'), giving clear selection criteria.

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