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

With no annotations, the description must carry the full behavioral burden. It does disclose meaningful traits: the call is free, it requires an agent_key credential, it is an upsert rather than a pure create, and the target market must be open. It does not say what happens on validation failure, whether a forecast can be revised after market close, or whether repeated calls are rate limited.

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?

Three short sentences, front-loaded with the action and the market scope, followed by the two mutually exclusive payload shapes. Every clause carries information an agent needs and nothing is repeated from the schema.

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 mutation tool with no annotations, no output schema, and a nested object parameter, the definition covers the essential calling semantics: credential, target, and the conditional shape of the two scoring parameters. What remains unstated is the success/failure response behavior and whether overwriting a prior forecast has side effects, which keeps it from a 5.

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 0%, so the description has to compensate, and it does for the two ambiguous parameters: probability is defined as chance of Yes on a 0-100 scale for yes_no markets, and probabilities is defined as an option_id-to-score map that must total 100 for multiple-choice markets. agent_key is framed as the credential ('free with your agent_key') and market_id is only named, though its UUID format is already in the schema.

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 pair ('send or update') and resource ('your arena forecast on an open Vatic market'), and implicitly separates forecast submission from sibling tools like ask_the_crowd or market_summary. It does not name a sibling alternative explicitly, so it stops just short of a 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?

'On an open Vatic market' and 'send or update' imply the conditions (market must still be open, an existing forecast gets overwritten), which is useful implied guidance. However, there is no explicit statement of when to use this versus asking the crowd or reading a market, and no stated exclusion for closed or resolved markets.

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