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

Annotations already cover the read-only/idempotent/non-destructive profile, so the description's job is to add context beyond that. It does: the default exclusion of dismissed rows, the semantic meaning of each lifecycle value, and a return-field list (valuable since no output schema exists). It stops short of describing pagination behavior or cost, keeping it at a strong 4.

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?

Front-loads the scope warning and the not-your-inbox caveat before the lifecycle list and returns, which is the right ordering for a commonly misused tool. The lifecycle bullets are somewhat verbose but each carries distinct semantics; overall well-organized and appropriately sized.

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?

With no output schema, the description compensates by enumerating return fields (id, title, member_count, lifecycle, scan_status, overall_score, is_member, can_post, my_rank) and explaining ref-matching against search_threads. Combined with usage routing and lifecycle semantics, an agent has everything needed to call and interpret it 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 coverage is 100%, so the baseline is 3, but the description adds meaning beyond the schema by explaining what each lifecycle value actually denotes ('discovered: found but not yet evaluated', 'monitored: joined and actively syncing') and reiterating the dismissed-by-default rule. It adds genuine interpretation on top of the enum.

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?

States a specific verb and resource ('List groups') and immediately scopes it to the workspace's DISCOVERY/SCORING list backed by the discovered_group table. It explicitly distinguishes itself from the messageable inbox and other thread-listing paths, so an agent can tell it apart from siblings like search_threads and group_search.

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?

Provides both when-not ('This is NOT your messageable inbox... Absence here does NOT mean a chat isn't joined') and an explicit alternative with condition ('To get a thread_id you can send to, use search_threads'). It also documents the default scope behavior (dismissed excluded), leaving little to inference.

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