Icu Get Custom Items

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

Annotations already declare readOnly/idempotent/non-destructive, so the description focuses on behavior: one call returns every custom item across all types, with an enumerated list of the type categories and the note that each item carries a `type` field so filtering is client-side. That is real behavioral context (no server-side type filter). It stops short of saying anything about result volume or pagination for large accounts, which is the main remaining unknown.

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 purpose, then usage triggers, then the return inventory, then exclusions — a clean information hierarchy. The long parenthetical enumeration of chart/field/stream/zone types is dense, but it earns its space by telling the agent exactly what comes back; the example utterances could be trimmed slightly without loss.

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?

An output schema exists, yet the description still summarizes the aggregate return shape and the per-item `type` discriminator, which is exactly the context an agent needs to decide between one broad call and a targeted one. Combined with the explicit exclusion routing, nothing needed to invoke it correctly is missing.

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 only one optional parameter and the schema already documents it at 100% coverage ('Athlete ID (for coaches managing multiple athletes)'). The description adds nothing about athlete_id — no default-athlete behavior, no coach-context guidance — so this sits at the baseline for a fully described single parameter.

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 ('List the user's custom additions to their Intervals.icu account') and immediately scopes it as read-only inventory of the user's own customizations. It distinguishes itself from siblings by naming the built-in equivalents (sport settings, profile data) that live in other tools, so an agent can route without opening any schema.

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 concrete trigger phrasings ('show my custom charts', 'what custom zones do I have') and an explicit exclusion clause: do NOT use for built-in zones, built-in fields, or athlete profile data, with icu_get_sport_settings named as the alternative. Both the when and the when-not are stated outright.

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