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

Annotations already establish read-only/idempotent safety, and the description adds real behavioral context beyond them: automatic fallback warning when |lat| > 66.5° for quadrant systems, plus the list of supported house systems. It does not mention cost implications or fallback target system, but the polar-latitude caveat is valuable and non-obvious.

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?

Dense but front-loaded: the first clause states what is computed, the second names systems, the third flags the edge case. No padding, and the group/cost tags are structured metadata rather than prose. Slightly compressed to the point of terseness but no wasted sentence.

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-format explanation is not required, and the description usefully enumerates the returned points anyway. However, for a 15-parameter tool at 33% schema coverage with no output-schema reliance for params, the description leaves several inputs (cosmogram, name/city, date/time handling) undocumented.

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 coverage is only 33% across 15 parameters. The description names the house-system families (Placidus, Koch, Regiomontanus, etc.), which maps names onto the opaque enum codes, and its latitude caveat relates to the latitude parameter. But date/time/longitude, cosmogram, name and city go unaddressed in prose.

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 verb and resource ('Standalone house calculation') and enumerates exactly what is returned: 12 cusps, ascendant, MC, ARMC, vertex, co-asc, polar-asc. The word 'Standalone' signals it is distinct from the full-chart sibling (astroway_western_chart), though no sibling is named outright.

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?

Implied usage only: 'Standalone' suggests reach for this when only houses are needed rather than a full chart, but there is no explicit when-to-use, when-not-to-use, or named alternative. An agent must infer the routing decision itself.

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