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

Annotations only say readOnly=false, openWorld=true, idempotent=false, destructive=false; the description adds the material facts an agent actually needs — that the call costs 5,000 credits at Tier 7, that this is roughly half a free monthly budget, and that user confirmation is required. The 'not a prophecy' disclaimer also sets expectations about the output's nature. This is genuine context beyond the structured fields.

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?

The prose is two compact sentences that front-load the report's content and scope, followed by clearly delimited bracketed metadata. Nothing is padded, though the disclaimer sentence is arguably low-value for tool selection.

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 an output schema present, the description need not explain return values, and the cost/premium warning covers the one high-stakes behavioral fact. The title signals PDF-or-HTML output but no parameter in the schema selects format, and no format explanation appears in the description — a minor gap, though not one the agent must resolve to call the 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 60%, and the description only restates the single required parameter ('Required: chart'). It adds nothing about the optional fields/compact-mode, language, precision, or whitelabel parameters, all of which are documented (at varying depth) in the schema itself. Baseline 3 is appropriate when the schema carries the load.

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 output (romantic-relationship natal report) and even names the four astrological factors it foregrounds (Venus, Mars, Moon, Descendant), which pins down what 'love report' means. An agent can distinguish this from the sibling astroway_reports_natal (general natal) and astroway_reports_synastry (two-chart relationship) reports without opening a 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?

The premium-cost warning and the explicit instruction to 'Confirm with user before invoking' give real invocation-time guidance that a sibling-selection rule does not. It does not, however, state when to prefer this single-chart love report over astroway_reports_synastry or astroway_reports_natal, so the alternative-selection guidance is left implicit.

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