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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and openWorld=false, so the safety profile is covered. The description adds genuinely useful context beyond the annotations — the cost (10 credits, Tier 1) and the endpoint — but it says nothing about what computation is performed or what the caller should expect, so the value is moderate.

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 definition is tight and front-loads the one descriptive phrase before bracketed metadata, with no filler sentences. The bracketed block is machine-oriented rather than prose, but it is compact and easy to parse.

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?

An output schema exists, so return-value documentation is not required. But for a 15-parameter calculation tool the description omits the conceptual result, any usage context, and all optional-parameter meaning, leaving the agent without enough to invoke it purposefully beyond the four required fields.

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 only 33% across 15 parameters, and the description's '[Required: date, time, latitude, longitude]' merely restates the schema's required array. The optional parameters (ayanamsa, timezone, houseSystem, fields, precision, cosmogram) get no explanation in the description, so it does not compensate for the coverage gap.

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 technique ('Constellations beyond the zodiac', Hellenistic Greenbaum tradition) and disambiguates itself as a cursor-friendly alias of astroway_hellenistic_greenbaum_sphaera_barbarica. However, it never states what the tool actually does or returns — no verb like 'compute' or 'derive the Sphaera Barbarica placements for a chart' — so the agent knows the topic but not the operation.

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 and no alternatives named. The bracketed metadata lists required inputs and cost but says nothing about the conditions under which this technique is appropriate, nor how it differs in use from related Hellenistic siblings (decans, dodekatemoria, temple doctrine).

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