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

Annotations only declare non-read-only, non-destructive, non-idempotent. The description goes well beyond them: tier limits with concrete numbers, refusal behavior that names the limit, write-scope auth requirement, and explicit side-effect scoping ('starts no bot and places no order'). This is exactly the context annotations cannot carry.

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-loaded with the core action and id return, then constraints. It is a dense single paragraph that covers a lot, though the tier-limit parenthetical and default enumeration make it longer than strictly necessary given the schema already lists defaults.

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 annotations, a full output schema, and 100% schema coverage, the description supplies the remaining unknowns: tier quotas, refusal semantics, auth scope, and the no-side-effect guarantee. Nothing an agent needs to invoke it safely 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%, so the baseline is 3. The description adds value by consolidating defaults (hybrid, min_confidence 60, direction all, 4h), noting only name is required, explaining that engines take ids from the schema's list, and clarifying that an empty symbols list means any pair and forces run_backtest to supply a symbol — the last point crosses parameter boundaries in a useful way.

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+resource ('Saves a new strategy on the API key's account and returns it with its id') and immediately distinguishes itself from update_strategy (change) and run_backtest (test). An agent can pick it out from the sibling list without opening a 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?

Explicitly routes the agent: use this to set up a strategy for run_backtest, use update_strategy to change one. It also states the required permission scope (write-scope key) and that it does not start a bot or place an order, so the when/when-not is complete.

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