Timeline (SVG)

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

Annotations already declare readOnly/idempotent/non-destructive, and the bracketed metadata adds real value by disclosing the endpoint, required fields and a 10-credit cost. Beyond that it discloses little behavior: not that format defaults to json (so an SVG is not returned unless requested), nor the 200-event cap, nor size/width bounds.

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 front-loaded sentences with no filler, followed by clearly separated metadata tags; nothing is wasted. It is arguably too terse rather than too long, but the structure is good.

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?

The output schema and annotations carry the return-value and safety story, but the tool has a deeply nested input (events objects and a seven-field options object) and the description explains none of it - not the event fields, not the display toggles, not the svg/json output choice. For a rendering tool of this complexity the prose is under-built.

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 is expected to compensate, and it only tells the agent that events is caller-supplied. The structure of an event (label/start/end plus optional exact/color/category) and the meaning of options such as rowHeight, showAspects and showRetrograde are left entirely to bare field names.

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?

Names a specific rendering artifact (Gantt-style horizontal timeline), the domain of the content (transit/aspect events) and the input shape (events over a date window). It is distinguishable from the wheel/cosmogram/biorhythm render siblings, though no sibling is named explicitly.

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?

'Caller supplies events array' usefully signals this is a pure renderer that draws data you already have rather than computing transits for you, which implies when to pick it. However there is no explicit when-to-use/when-not and no pointer to related tools such as the aspect-timeline or transit-calendar endpoints that could produce the events.

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