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 externally. The description adds real value beyond annotations by disclosing cost (20 credits, Tier 2), the endpoint, and required inputs. It stops short of noting response size or how the optional aspect inclusion is toggled, so a 3 is appropriate.

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?

Front-loaded with the core purpose in the first sentence, followed by a short optional extension, then a compact bracketed metadata block. No filler sentences. The metadata block is dense but scannable and each line carries operational value.

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 values need no prose, and annotations cover safety. But for a 15-parameter tool with only 33% schema coverage, the description leaves substantial gaps around which parameters enable sidereal mode, house system choice, and the compact-mode fields/precision options. It is minimally viable rather than complete.

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, so the description is expected to compensate and does not. It restates the four required inputs and vaguely alludes to an optional aspect toggle without naming the controlling parameter. Key knobs such as zodiacType, houseSystem, ayanamsaId, precision, and cosmogram receive no explanation in the description.

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: 'Calculate all planetary midpoints and their zodiac positions,' with an optional aspect extension. An agent can tell it computes midpoints rather than, say, midpoint trees or antiscia. However, it offers no explicit contrast with the close sibling astroway_aspects_midpoint_trees, so differentiation relies on the name alone.

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?

No when-to-use guidance, no prerequisites, and no mention of alternatives like astroway_aspects_midpoint_trees or astroway_aspects_aspect_bar. The only contextual markers are the required-inputs and cost lines, which inform feasibility rather than selection. The agent must infer the use case entirely.

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