search_messages

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the agent knows this is a safe, read-only operation with limited scope. The description adds useful context about the default search scope ('only searches contacts you've messaged') and the include_all override, but doesn't provide additional behavioral details like rate limits, performance characteristics, or error conditions.

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 perfectly concise with just two sentences that are front-loaded with the core purpose. Every word earns its place: the first sentence establishes scope and capabilities, while the second clarifies a critical default behavior. There's zero redundancy or wasted verbiage.

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 search tool with comprehensive annotations and full parameter documentation, the description provides adequate context about scope and default behavior. The main gap is the absence of an output schema, leaving return format unspecified. However, given the tool's read-only nature and clear purpose, the description provides sufficient guidance for basic usage.

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?

With 100% schema description coverage, all 11 parameters are well-documented in the input schema. The description provides high-level grouping of filter types ('query text, contact, date range, direction, group chat, and attachment filters') and clarifies the include_all default behavior, but doesn't add significant semantic value beyond what's already in the detailed parameter descriptions.

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 tool performs 'full-text search across all iMessages with rich filtering', specifying both the verb ('search') and resource ('iMessages'). It distinguishes itself from siblings like 'get_conversation' or 'get_thread' by emphasizing comprehensive search capabilities rather than retrieving specific conversations or threads.

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 clear context about when to use this tool ('full-text search across all iMessages') and includes one explicit usage note about the 'include_all' parameter default behavior. However, it doesn't explicitly contrast when to use this versus alternatives like 'get_conversation' for specific threads or 'list_contacts' for contact-focused operations.

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