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

Beyond the readOnly/idempotent annotations, it discloses real behavioral traits: a 90-day and 1,000-observation cap, the aggregation rule (currencies kept separate, platforms/editions/regions merged), explicit coverage and truncation reporting, and the caveat that gaps mean non-continuous data. These are exactly the traits that would cause a wrong conclusion if unstated.

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 dense sentences, with the positive capability and its caps front-loaded and the disclaimers trailing. The final clause is a compressed list of three negations that reads tersely but each element earns its place.

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 does the work of telling the agent what kind of result to expect (discrete observations over a window, not a continuous chart) and that truncation is reported. What it omits is the default window behavior and the exact shape/ordering of returned observations, which an agent would only learn by calling.

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 0%, so the description carries the burden. It partially compensates: it caps 'days' at 90 (matching the schema maximum) and clarifies that 'slug' must be a confirmed public slug. It gives no guidance on the default 30 days, on the meaning of the 1,000-observation cap relative to the window, or on how coverage/truncation are surfaced.

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 verb and resource (retrieve recorded GameDeal price observations) with hard scope limits (90 days, 1,000 observations, one public slug), and rules out misreadings such as 'market low' or 'availability chart'. It never names its siblings get_game_offers or search_games, so the agent must infer the boundary itself.

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?

'For a confirmed public slug' implies a prerequisite (resolve the slug first, presumably via search_games) and the closing clause implies when-not-to-use this tool (market-low or availability questions). There is no explicit routing statement telling the agent when to pick this over get_game_offers, so usage is only implied.

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