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

Annotations already declare destructiveHint=false, openWorldHint=false, and idempotentHint=false, so the safety profile is largely covered. The description adds genuinely useful context beyond that: 'Free, no key' (no auth/cost) and 'Signed with the receipt key' (attested output). However, readOnlyHint=false sits awkwardly against a purely view-oriented 'snapshot' framing, and the description never resolves that tension or notes any side effect of repeated calls.

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 purpose and the closing sentences ('Free, no key', the ask_market pointer) clearly earn their place. But the output enumeration is delivered almost entirely in metaphor ('their lamp burns', 'the reference agent's last walks', 'the sealed days of the register'), which costs decoding effort rather than being genuinely concise.

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 no output schema, the description carries the return-value burden and does describe the returned sections (lanes/stalls, sales, unmet demand, activity, register days, narrative scene) plus auth/cost context. Given the low complexity (one optional param, no nesting), this is nearly complete, though the metaphor leaves the exact return shape slightly fuzzy.

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?

There is one optional parameter (stalls_per_lane) with 100% schema description coverage, so the schema already documents range and default. The description adds nothing about the parameter, which is acceptable per the high-coverage baseline but means no extra value is contributed here.

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 names a specific resource (the market) and enumerates the concrete content it returns: lanes (categories) with stalls (listings) in ranking order, paid sales, unmet demand, agent activity, register days, and a narrative scene. The parentheticals decode the metaphor enough that an agent can identify this as a market-overview/snapshot tool, and it explicitly contrasts itself with ask_market.

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 gives an explicit alternative and the condition that selects it: 'To find something for a goal, use ask_market.' That is real routing guidance rather than implied usage. It stops short of a 5 because it does not address other plausible overlaps (e.g. market_insights, search_listings) or state when NOT to call this.

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