Read iPhone widget data

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

Annotations already declare readOnlyHint and openWorldHint, and the description adds a genuinely useful operational fact: it authenticates with WIDGETDASH_READ_KEY, falling back to the write key when no read key is set. It also indicates the return payload contains metrics and last update time, though it does not detail error or auth-failure behavior.

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 tight sentences, no filler, with the primary behavior (what is shown on the widget) front-loaded ahead of the mode switch and the auth note.

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 burden of describing results and does so at a high level (enabled sources, metrics, last update time) plus the auth mechanism. A slightly fuller sketch of the returned structure would close the remaining gap for an open-world read tool.

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 100% and the parameter's description already explains that omitting it returns all sources. The description's 'or one source if source_key is given' restates the schema rather than adding format or constraint detail, so the baseline 3 applies.

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: reading what is currently displayed on the user's WidgetDash iPhone widgets, including metrics and last update time. That framing (current widget state) is distinguishable from generic source management, though the distinction from list_sources is only implicit.

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 selection logic for the two modes: omit source_key for all enabled sources, supply it for a single source. It does not explain when to prefer this over the sibling list_sources, which appears to overlap in returning source information.

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