search_messages

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

With no annotations, the description carries the full disclosure burden, and the "~15s indexing delay" is a genuinely valuable behavioral fact the agent cannot get elsewhere. However, it omits result limits, ordering, pagination, and permission scope for a search tool over potentially large history — meaningful gaps when nothing else covers them.

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?

Two short sentences, no filler, with the core purpose and the freshness caveat front-loaded before the exclusion. There is no redundancy or padding to trim.

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 indexing delay and the schema's parameter documentation cover the basics for a five-parameter search tool. Still, with no output schema and no annotations, the description says nothing about what results look like, how many are returned, or their ordering, which an agent needs to use the results correctly.

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 100%, so all five parameters are already documented, including the strong "MUST ASK. DO NOT GUESS." guidance on text. The description adds only the phrase "text query," contributing nothing beyond the schema, so the baseline of 3 applies.

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 pairs a specific verb and resource ("Search message history") with the retrieval mechanism ("by text query"), which distinguishes it from single-message siblings like get_message_via_id. The added exclusion ("Do not use for user/channel ID lookups") muddies the line, however, since the schema itself exposes fromUserIdentifiers and inChannelIdentifiers as filters, leaving the intended boundary with list_users_not_for_id_lookup only implied.

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?

It supplies one negative rule and a freshness caveat, giving some context for tool selection. But no alternative is named for the excluded case, and it never tells the agent when to prefer list_messages_via_name_or_id or get_message_via_id over this search, which is the main routing decision among these siblings.

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