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

Annotations (readOnlyHint=false, idempotentHint=true) don't explain the plan limits or the side effect, but the description does: Starter returns 5 items, Pro up to 25 with multiple profiles, and the first call for a non-subscribed account carries an emailOffer flag once per account. It also discloses that the same items are delivered to the daily e-mail, which explains the non-read-only annotation.

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?

Front-loaded with the core definition and signal list, then the item shape, then plan tiers and the subscribe hand-off. Dense and parenthesis-heavy, and the per-field item list overlaps the output schema, but no sentence is idle.

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?

Given an output schema, the definition still covers the things structure can't: signal semantics, tier-based result caps, the one-time emailOffer side effect, and the subscription sibling. An agent can call it correctly and explain its output without further context.

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 coverage is 100% and both enum parameters are already documented with defaults, so the description only restates window='week' and does not add formating or defaulting detail beyond the schema. The reference to why/factors language aligns with, but does not extend, the lang parameter's own description.

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 ('the top aircraft that ENTERED a signal in the last 24 hours') tied to the connected account's interest profile, and enumerates the five signal types. This is unmistakably different from sibling tools like jt_signal_ranking or jt_sale_propensity, which cover single signal families.

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?

Gives clear usage context (daily digest, window='week' for a 7-day view) and routes the user to jt_today_subscribe when they want the daily e-mail. It stops short of explicitly saying when to prefer this over ranking-focused siblings, so the alternative-routing is only partially covered.

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