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

Annotations already declare readOnlyHint, destructiveHint=false, openWorldHint=true and idempotentHint=false. The description adds genuinely useful operational context by disclosing the cost (100 credits, Tier 4) and the AI grouping, which helps an agent budget. It does not explain the non-idempotent nature of an AI-generated explanation or any latency/rate behavior, so it adds some but not rich value.

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?

A single front-loaded sentence carries the core purpose, with the group and cost tags kept as structured metadata rather than prose. It is tight and waste-free, though its brevity edges into under-specification rather than model conciseness.

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?

For an 8-parameter tool with a nested chart object and five required fields, the description omits routing guidance against several plausible siblings and says nothing about the transit inputs. The presence of an output schema excuses it from describing return values, but the selection and input story is still incomplete.

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 38% and the five required parameters (chart, transitDate, transitPlanet, natalPlanet, aspectType) carry no schema descriptions at all. The description only obliquely implies a transit/natal pairing and says nothing about expected values or formats for those required fields, 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 states a specific verb and resource: 'Explain' applied to 'a current transit hitting your natal chart.' An agent can tell what the tool produces. It stops short of distinguishing itself from close siblings such as astroway_mcp_ai_explain_aspect or astroway_reports_ai_transit_narrative, so it is clear but not sibling-differentiating.

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, when-not-to-use, or named alternative. The sentence implies the context (a transit to your natal chart) but gives no condition that would route an agent here instead of the aspect explainer or the transit narrative report. This matches the 'no guidance' band.

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