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

Annotations cover the safety profile (readOnlyHint=false, destructiveHint=false), and the description goes well beyond them: it discloses firing cadence (once per trading day; checked daily on closed values), idempotent re-request behaviour for world_price_target and composite_zone_change (returns the existing rule with created=false), the quota ceiling, and the permission required. It also warns that the call mutates the account. No contradiction with annotations — the per-type idempotency note refines, rather than conflicts with, idempotentHint=false.

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 action and effect, then organized per rule_type, so the structure is easy to scan. It is very long, and the zone-scale enumeration (extreme_fear/fear/neutral/greed/extreme_greed with numeric bounds) is verbose, but almost all of it is load-bearing given the five distinct rule shapes.

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 complex tool with a nested params object and five variants, the description covers selection, per-type arguments, mutation semantics, idempotency, limits, permissions and the user-facing constraint on near misses. An output schema exists, so return values need not be elaborated, yet the created/rule_id shape is briefly and harmlessly confirmed.

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?

Top-level schema coverage is 100%, but the nested params object is entirely undocumented in the schema ('as listed in the tool description'), so the description carries the full burden and does so precisely: it names every sub-field per rule_type (threshold, currency, market, symbol, price, direction, slug, price_usd, spec_id, zone) with types, units and which are required. It also explains the ticker applicability rule and the zone-only representation of indicator thresholds.

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 ('Create an alert rule in the user's account') and immediately describes the observable effect (notification in the notification centre and enabled channels). It is trivially distinguishable from siblings such as alert_delete and alerts_list, and it enumerates the five rule types the server accepts.

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 explicit routing per rule_type with the conditions each expresses, plus an explicit negative instruction: 'Do not use this tool for a condition these types cannot express: tell the user instead of silently creating a near miss.' It also states the hard ceiling (agent rule limit) and the required 'alerts' permission, which are genuine preconditions rather than implied context.

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