acg_hits

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is clear. The description adds useful behavioral context beyond annotations: it states results are 'sorted by distance' and mentions the credit cost (15 credits per call). It does not contradict 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?

The description is well-structured with a clear purpose statement, usage examples, explicit exclusion, credit cost, and a practical example. Every sentence adds value, and the formatting (bold, checkmarks) improves scannability without unnecessary verbosity.

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 a read-only, read-only tool with no output schema, the description gives a general idea of the return ('Returns features sorted by distance') and provides a full usage example. It does not detail the exact output format, but given the tool's simplicity and the annotations, this is sufficient. A 4 is appropriate.

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 100%, so the baseline is 3. The description adds a concrete example showing how all key parameters map to real values (e.g., birth_datetime, timezone, query_latitude, radius_deg), which enhances understanding beyond the schema alone. This justifies a 4.

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 clearly states the tool's function: 'Find all Astrocartography lines (power lines + aspect lines) passing near a specific location.' It identifies the specific resource (ACG lines), the verb (find), and the scope (near a location). It also distinguishes itself from the sibling tool acg_power_lines by explicitly noting it's NOT for full global map geometry.

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 provides explicit when-to-use examples ('Is [city] good for me?', 'What planets affect me in Tokyo?') and an explicit exclusion with an alternative ('NOT FOR: Full global map geometry → use acg_power_lines for that instead.'). This fully guides the agent on tool selection.

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