Join a case jury

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

Annotations only establish a mutating, non-idempotent operation; the description adds substantial context beyond that: the safety-critical disclosure that the server performs no invite-list check, specific failure modes (400 for closed/already-seated/no-slot, 403 arbitration_owner for the case owner), the lifecycle rule that leaving is refused once you've voted, and the {success, message} return shape since no output schema exists. No contradiction with the annotations.

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?

Seven sentences, every one earning its place: core action, usage condition, safety warning, sibling differentiation, error codes, lifecycle, and return shape. It is front-loaded pyramid-style with the primary action first and supporting constraints after, and nothing repeats what the schema or annotations already state.

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 the single parameter fully documented in the schema and no output schema, the description correctly carries the burden of error behavior, return shape, and the invite-check gap. Given the nuanced three-mode jury semantics and numerous close siblings, nothing an agent needs to invoke this tool correctly is missing.

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%: the caseId property already carries a full description including its provenance (tribeunal_get_case, tribeunal_search_cases, or a jury invitation) and a UUID pattern. The description's case-type distinction (invited-jury vs wait-mode vs public) adds domain context about valid targets, but it does not add syntax or format detail beyond the schema, so the 100%-coverage baseline 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 opening sentence 'Seat yourself on a case's jury' pairs a specific verb with a specific resource. It also distinguishes from close siblings: tribeunal_join_tribe is explicitly called out as joining a standing group rather than a case, and tribeunal_cast_vote is named as the direct-vote alternative for public juries. An agent can tell this tool apart from its relatives without opening any schema.

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 explicit positive conditions ('Use when invited to an invited-jury case, or a wait-mode case needs jurors'), a concrete exclusion ('public juries need no seat, vote directly with tribeunal_cast_vote'), and names alternatives tribeunal_join_tribe and tribeunal_invite_jurors. It also adds a hard constraint not inferable from the schema: never join a jury you were not invited to, because the server does not check the invite list.

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