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

Annotations already declare readOnly, idempotent, closed-world, non-destructive, so safety is covered; the description adds two things they do not: the draw is date-seeded (i.e., reproducible for a given date rather than random) and it costs 10 credits at Tier 1. Cost and determinism are genuine invocation-relevant facts for an agent budgeting calls.

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?

One tight sentence carries the core behavior, with group and cost metadata in bracketed tags that scan quickly. Nothing is redundant, though the sparseness means some agent-facing questions go unanswered rather than being deliberately omitted.

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 zero-required-parameter tool with an output schema, the return-value burden is lifted, and annotations cover the safety profile. Still missing: whether `date` defaults to today, and any routing signal versus the near-identical three-card and other-tradition daily siblings, which is the main risk for this agent.

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?

With 67% schema description coverage, the schema documents `fields` and `precision` in detail, so the description need not repeat them. It only gestures at `date` via 'based on date seed' and never states the expected YYYY-MM-DD format or that the parameter is optional and defaults to today, leaving a small gap the schema's bare pattern does not fill.

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?

The description names a specific verb and resource ('daily three-card draw') and adds the generative mechanism ('based on date seed'), so an agent knows this is a deterministic, date-keyed draw rather than a random one. It does not name the very similar sibling astroway_tarot_lenormand_draw_three_card, so the distinction is inferable but not stated.

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?

Nothing says when to pick this over astroway_tarot_lenormand_draw_three_card, astroway_tarot_marseille_daily, or astroway_tarot_rider_waite_daily. The word 'Daily' hints at a daily-card-of-the-day use case but no alternative or exclusion is given, so the agent must guess.

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