Depth concentration today

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

Annotations already declare readOnlyHint, idempotentHint and a closed world, so the safety profile is covered. The description adds genuinely non-structured behavior: the output is BTC-only and two-sided, and subscriber tier changes both coverage (ETH) and content (venue failure). It does not state freshness or timeframe, which the title ('today') hints at but the description omits.

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?

Two short, front-loaded sentences with no filler — the metric list leads and the tier caveat follows. The dense jargon ('effective/top venue', 'exit_desk_full') is compact but requires domain familiarity to parse.

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 parameterless, single-purpose metric tool with no output schema, the description names the returned measures and the tier-gated extension, which is close to sufficient. It stops short of describing the metric units/definitions or the evaluation window, so an agent cannot fully predict the response shape.

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?

Zero parameters, so schema semantics carry no burden and the baseline is 4. The description reinforces the fixed scope ('BTC two-sided depth'), implying no filtering arguments are expected.

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 resource and metric set: 'BTC two-sided depth: HHI, effective/top venue and venue depth', which tells an agent exactly what is computed. It does not name or contrast any sibling (e.g. liquidity_tiers or venue_price_reconciliation), so differentiation is left to inference.

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 second sentence implies a usage condition — the exit_desk_full subscription unlocks ETH and venue-failure data — but there is no explicit when-to-use or when-not-to-use guidance versus the many other liquidity/venue siblings. The tier note is a helpful access precondition rather than selection guidance.

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