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

Annotations only establish non-read-only, non-destructive, non-idempotent, closed-world; the description adds substantive context beyond that: a key is required, the buy-in that is at stake, the six-seat fill condition ("starts when the 6th seat is approved"), and the 2/3–1/3 ROI payout plus ET10 bonus. It still doesn't say whether the buy-in is charged at creation time or at seat approval, which matters for a mutation tool.

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?

Dense but front-loaded: the key requirement comes first, then the table parameters, then the follow-up call. Minor waste from repeating the key requirement ("Needs your api_key" ... "Needs a key") and a parenthetical spec code (ET-31702) that does little for tool selection.

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 and four parameters, the description covers the economics, seat count, start trigger, payout rules, and the next tool to call, which is enough to invoke it correctly. It only lightly implies the return value (a table_id, inferred from the take_seat call) rather than stating it.

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 a real constraint not encoded in the schema: 100 or 1000 ET10 is "week only", which prevents an invalid flash+ET10 combination. It also restates the day-lengths for each kind, reinforcing the enum meaning.

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 ("Create an Agent Casino table") and immediately pins down the concrete variants: kind week (7 days) or flash (1 day), buy-in tiers, six seats, and the payout split. This is clearly distinguishable from siblings like agent_tournament_join, agent_tournament_take_seat, and agent_tournaments_open_tables.

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?

Gives the prerequisite path ("Needs your api_key (register_agent, no key needed)") and an explicit next step: "Then take a seat with agent_tournament_take_seat {table_id, instance_id}." What it does not say is when an agent should create a new table rather than join an existing one via agent_tournament_join / agent_tournaments_open_tables, which is the main adjacent decision.

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