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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds real context beyond that – a cost of 10 credits (Tier 1) and the POST endpoint – which an agent budgeting calls needs, but says nothing about result shape or cost-sensitive behavior beyond the flat price.

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?

Four short lines with the purpose front-loaded and only machine-relevant metadata (group, endpoint, cost) following. No sentence is padded; the only mild inefficiency is that the bracket metadata is structured like tags rather than prose.

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 a rich input schema, an output schema, and full annotations, the description's omission of return-value detail is acceptable. The remaining gap is routing: in a namespace containing astroway_prognostics_profections and astroway_helb_profections_detail it never says what 'detail' adds or when this Brennan variant is the right choice.

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 embedded birth-data object is documented in exhaustive detail, so the baseline of 3 applies. The description contributes nothing about parameters, notably not explaining targetAge, the single required key that actually distinguishes this call from a plain natal chart.

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 phrase 'Annual profection year-lord with full classical condition' names a specific astrological computation and its scope ('full classical condition'), and the [Hellenistic: Brennan tradition] group tag separates it from greenbaum/schmidt/helb profection siblings. It is however a noun phrase with no verb, and it does not explicitly contrast with astroway_prognostics_profections or astroway_helb_profections_detail.

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?

There is no when-to-use guidance, no prerequisites, and no statement of when to prefer this over the other profection tools in the namespace. The 'annual' phrasing implies a yearly time-lord context but nothing tells the agent which sibling to pick for a non-Brennan or non-detail request.

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