search_messages

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

With no annotations, the description carries the full burden and does so excellently. It discloses non-obvious behaviors: default 7-day window, UTC interpretation of timezone-less values, and the sequential dialog-scanning bias in global search that affects result selection.

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?

Every sentence adds necessary context. The first line states the core action, and the following sentences pack in important semantics without fluff. The structure is front-loaded and easy to scan.

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?

The description covers the tool's core behavior, parameter nuances, default behavior, and a significant caveat about global search ordering. An output schema exists, so return-value details don't need to be repeated here. Nothing essential is missing for correct invocation.

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?

Schema description coverage is 0%, so the description compensates fully. It explains chat (omit for global), since_date (ISO 8601 default behavior, timezone handling), limit (stops global search), and query (searched in message text). This goes well beyond the raw schema.

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 opens with a specific verb and resource: 'Search message text globally or in one chat.' It clearly distinguishes the two modes and, by naming 'message text,' separates this from siblings like get_messages, search_files, or search_disclosures.

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 gives clear context for when to use global vs. scoped search and how to control the time window via since_date. It doesn't explicitly name alternative tools or exclusions, but the usage conditions are stated well enough for an agent to decide.

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