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. The description adds meaningful behavioral detail: exact output mapping, the full list of sphutas included, the output format with an example, and the explicit statement that no interpretation is added. This goes beyond what annotations provide.

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 description is efficient and information-dense without fluff. It opens with the action, immediately describes the output format with a concrete example, lists the included sphutas in a compact enumerative sentence, and closes with a one-line behavioral boundary. Every sentence contributes essential decision-making or invocation information.

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?

There is no output schema, so the description correctly takes on the burden of explaining the return format and the full set of results, which it does thoroughly. It also clarifies that this is raw data, not interpretation, which is an important contextual signal. For a read-only, idempotent computable tool, nothing essential is missing.

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?

The input schema already describes all parameters with 100% coverage, so the baseline is 3. The description does not add parameter-specific semantics beyond 'of the chart' and the note that data-only output; it does not document date/time/coordinates because those are already fully covered in the schema. It neither harms nor significantly enhances schema coverage.

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: 'Return the sphutas (special computed sensitive points) of the chart.' It clearly explains what the output is (sphuta name → zodiacal position in sign/degrees/minutes/seconds) and enumerates all included sphuta types, leaving no ambiguity about what the tool provides.

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?

The description gives clear context by noting 'Data only — no interpretation is added,' which tells the agent to reach for this tool when raw computed sphuta positions are needed rather than interpretive analysis. It does not explicitly name an alternative tool or state exclusionary conditions, but the usage context is clear enough among the many sibling tools.

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