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

With no annotations, the description carries the full burden and does well: it discloses that nothing is sent (no side effects), that the quote is time-limited (seconds), that it returns exact calldata rather than executing, and that a session_key triggers live TRADE-session, spendLeft and riskLeft checks. It doesn't state permission/auth prerequisites beyond the session-key case or describe error shapes beyond the close_only:* marker.

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?

No sentence is wasted, but it is a single dense run-on paragraph with nested parentheticals and inline backticks, making it hard to scan. The core quote/return facts are front-loaded, while the session-key parenthetical buries useful detail mid-sentence.

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 5-parameter, no-annotation, no-output-schema tool, the description covers what the tool is, what it returns, its safety profile (nothing sent) and its error routing. Only the parameter format details (quantity units, instrument format) and any auth preconditions remain underspecified.

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 must compensate, and it does for all five parameters: `side` is buy or sell, `quantity` is shares, `account` is the addressed owner, and `session_key` is optional and changes the validation performed. It doesn't clarify the string encoding of quantity (decimals/units) or what `instrument` identifiers look like, which are the main gaps.

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 states a specific verb and resource (a signed, fillable quote for `quantity` shares on an `instrument`) and enumerates what the caller gets back: calldata for fillOrderAs, fee, decay and a canFill preview. It also distinguishes the tool from the sibling `close_quote` in the same breath, so an agent can route between them without opening either 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?

It clearly frames the buy path and gives an explicit exclusion with a redirect: sells are close-only against a long `account` holds, otherwise you get close_only:* and should use `close_quote` instead. What's missing is any guidance on how this differs from the borrow_*/lend_*/vault_* quote siblings, but those are distinct domains an agent can infer from their names.

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