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

With no annotations, the description carries the full burden. It discloses a $0.001 USDC per call fee, states a ~15-minute refresh interval, and implies a wallet may be required by mentioning it in context of the free preview. It does not describe side effects beyond being a read operation, which is appropriate.

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 description is a single sentence but is structured with semicolons and dashes, front-loading the main purpose and then detailing contents. Every phrase adds value, but its length is a bit dense for a single sentence, so a 4 rather than 5.

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?

The description thoroughly covers what the tool returns, including the universe coin count, regime gate, phase clock, receipt contents, refresh rate, and cost. With no output schema, it conveys all necessary return information. It is complete for a zero-parameter read tool.

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?

The tool has zero parameters, so the schema is trivial. The description does not need to add parameter details, and it doesn't contradict any schema. With no parameters to document, a baseline of 4 is appropriate.

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 clearly states the tool provides 'the FULL overnight continuation read' with a detailed list of what it returns (top-5 coins, BTC regime, phase clock, eligibility counts, receipts). It distinguishes from the sibling get_crypto_night, which is a free preview trimmed to the #1 coin.

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?

The description implies when to use the full version versus the free preview by mentioning 'No wallet? get_crypto_night is a free live preview'. It also mentions cost and refresh interval, but does not explicitly state 'use this when full details are required' or exclude other cases. The comparison with the sibling tool provides clear context.

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