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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely new context by disclosing the cost (100 credits, Tier 4) and the POST endpoint, which is real pre-call information. It says nothing about latency, rate limits, or what the progressed calculation consumes, so it stays at a 3.

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 dense sentence that front-loads the purpose, followed by three compact metadata lines (group, endpoint, cost). Nothing is padded, and the most important information comes first, though the Cost/Endpoint block is boilerplate rather than prose.

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 no explanation, and the deep input schema covers all three top-level parameters. What is missing is the relationship to the many sibling geo endpoints, which matters for an agent choosing among ~15 geo tools. Adequate but with a clear gap.

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 schema already documents natal, targetDate, orb, point/latitude and the compact-mode fields thoroughly. The description adds only loose framing ('at a target date', 'latitude crossings') and no syntax or format detail beyond the schema. Baseline 3 for a schema that does the heavy lifting.

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 ('Analyse Cyclo-Carto-Graphy (CCG) lines') and expands the acronym, then narrows it to 'progressed A*C*G lines at a target date with mundane/local aspects and latitude crossings.' That distinguishes it in substance from the natal-oriented astroway_geo_acg, though it never names a sibling outright.

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 no when-to-use or when-not-to-use guidance and never points at a neighbouring geo tool (acg, acg_best_places, local_space, solar_acg, relocation). The only routing signal is the cost line, which is not a selection criterion. An agent must infer the CCG-vs-ACG choice on its own.

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