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

Far beyond the annotations, the description discloses that this is a paid $0.25 x402 tool requiring a PAYMENT-SIGNATURE header, that results carry LIVE/RECENT/SNAPSHOT/UNVERIFIED freshness labels, that empty results return WAIT rather than invented data, that a signed receipt is produced, that quotes may be stale, and that no trades are placed. These are exactly the operational traits an agent needs before spending money.

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?

It is front-loaded with the price and the request shapes, which is good, but the middle is a chain of em-dash fragments and parentheticals that is denser than it needs to be. Most sentences carry real information, yet the packaging makes it harder to scan than the content warrants.

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?

With an output schema present, return-value detail is not needed, and the description still covers payment mechanics, idempotency, budget gating, and result labeling. The remaining gap is the absence of any sibling/alternative framing, which matters in a 23-tool surface.

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 query, max_rows, objective, budget_usd, and idempotency_key, including example query strings and supported objective values. The description adds only the informal query phrasing ('COMPARE two tickers', 'BEST a theme'), which largely duplicates the schema, so the baseline 3 applies.

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 concrete action (shop an economic idea for $0.25) and enumerates the three request shapes it accepts: a single ticker scan, a COMPARE head-to-head, or a BEST theme. That is enough for an agent to know what comes back (ranked expressions within a budget). It loses a point because the name 'ticker_shelf' and the title 'Compute History' point in different directions and the description never reconciles them.

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 describes the input patterns it supports (ticker / COMPARE / BEST) and notes that an empty set returns WAIT, which implies a budget-gating use case. However, it never says when to prefer this over any sibling (e.g. compute_spot_prices, compute_alerts) or what conditions make it the wrong choice, so routing is left to inference.

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