Symbolic Directions

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely separate context the annotations do not: the endpoint, the Prognostics grouping, and a 50-credit / Tier 3 cost, which matters for an agent budgeting calls. No return-format detail, but an output schema exists.

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 core sentence is front-loaded and dense, with the key enumeration immediately after it. The bracketed group/endpoint/cost lines are compact metadata rather than prose filler, though they sit in the description where structured fields might be preferable.

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 not be explained, annotations carry the safety profile, and the schema fully documents natal/target inputs. The description supplies the remaining decision-critical piece — the directional key options and their meanings — plus cost.

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 100% and the nested body schema is extensively documented, so the baseline would be 3. The description goes beyond it by naming the default for 'key' (one_degree) and glossing solar_arc as 'the arc of the progressed Sun', meaning the schema's bare enum values do not carry.

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 symbolic arc directions to natal points for a target date' — which is precise enough to separate it from progressions or profections in the Prognostics group. It does not explicitly name the sibling it is not (e.g. astroway_prognostics_primary_directions), so sibling differentiation is left to the agent.

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?

Usage is only implied: the phrase 'for a target date' signals a predictive/timing context, but nothing states when to pick symbolic directions over primary directions, secondary progressions, or minor progressions. No prerequisites or exclusions are given.

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