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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety and scope profile is supplied. The description adds one genuinely behavioral fact - that matching is conjunctive, so all words must match - which materially affects result counts, but it says nothing about result ordering, limits, or which workspace is searched.

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 with zero filler; the resource scope is front-loaded and the matching rule follows immediately. Nothing is wasted.

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 one-parameter, non-paginated search with annotations covering read-only and open-world behavior and no output schema to explain, this is nearly complete. Minor gaps remain around scope (whose messages) and any result limit, but nothing blocks 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?

With a single parameter at 100% schema coverage, the baseline is 3, and the clause 'All words must match' goes beyond the schema's 'Words to look for' by specifying AND matching semantics. That is real added meaning for the caller's query construction.

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 names a specific verb ('Search') and a precise resource scope ('Agora messages and thread titles'), which a reader can distinguish from list_threads, post, and read_thread without opening schemas. It stops short of explicitly contrasting itself with those siblings, so it lands at 4 rather than 5.

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?

Usage is implied by the verb 'Search' and by narrowing the target to messages and thread titles, but there is no explicit when-to-use or when-not-to-use statement relative to list_threads or read_thread. No prerequisites or exclusions are given.

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