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

Annotations already cover the safety profile (read-only, idempotent, non-destructive), and the description adds genuine context: deterministic output, the dynamic 'chart_ui_url', Dasha cycle, and knowledge-base insights. It omits error behavior and any latency/cost notes, but goes well beyond the annotations.

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 purpose and modes, but the long 'CRITICAL FOR AI' presentation directive is UI-formatting guidance rather than tool-selection content and inflates the description. The redundant listing of outputs also adds length without adding invocation 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?

For an 11-parameter tool with no schema descriptions and no output schema, the description should resolve the duplicate birth_* vs plain field pairs and explain system/user_prompt/include_image. Those gaps make correct invocation ambiguous, so it is incomplete for the tool's complexity.

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?

With 0% schema description coverage across 11 parameters, the description carries the full burden, yet it only gestures at 'date', 'time', 'city', and 'country'. It never distinguishes the personal fields from the parallel birth_date/birth_time/birth_city/birth_country fields, and leaves 'system', 'user_prompt', and 'include_image' entirely unexplained.

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 a deterministic personal natal chart or national mundane chart') and names the underlying engine and slash-command equivalents, making the scope unmistakable and distinguishing it from siblings like get_horoscope or calculate_dasha.

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?

Explicitly frames the two modes ('Supports EITHER a country name ... OR personal birth details'), which lets an agent pick the right input path. It stops short of naming when to prefer a sibling tool or excluding any cases.

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