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

With no annotations provided, the description carries the full behavioral burden and does so well: it discloses budget accounting, settlement refunds, human-equivalent stake and position limits, idempotent retry behavior, and price-change handling via odds_changed. It also surfaces the authentication requirement and balance prerequisite before invocation.

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?

The purpose is front-loaded in the first clause, and the paragraph is dense but every sentence covers material behavior an agent needs before placing a financial bet. There is no repetition of schema-only details or filler.

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 complex financial mutation with no output schema and no annotations, the description is complete enough to call correctly: it covers prerequisites, stake source, limits, idempotency, fixed-odds price protection, and the odds_changed confirmation path.

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 the schema already documents all six parameters. The description adds meaningful cross-parameter semantics: expected odds and line version are only for fixed_odds markets, they work together, and idempotency_key must be unique per bet but reused on retries.

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 opens with a specific verb and resource: back yes or no on a prediction market using sats from the agent balance. It clearly distinguishes this action from market browsing or position-checking siblings such as prediction_markets and prediction_positions.

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 explicitly explains when to pass expected_odds_pct and expected_line_version for fixed_odds markets, what an odds_changed reply means, and that idempotency_key must be reused on retries. It also states the prerequisite of an agent key with balance and directs users to fund_agent first.

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