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

Annotations already declare a safe, read-only, idempotent, closed-world operation, so the bar is lower. The description still adds real value beyond them: it says every finding cites its rule card (traceability/return behavior) and explicitly states 'No loss-of-sibling claims', a meaningful scope/safety limit an agent must know before presenting results.

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?

Length is reasonable, but the opening clause front-loads book titles and version codes ('Brothers v15, v17, v24; Speech v29') before telling the agent what the tool is for. The trailing scope caveat is well placed, but the middle is a list of astrological factors with limited payoff for tool selection.

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-value explanation is not required, and annotations cover the safety profile. What is missing is input guidance: for an 8-parameter chart tool with two mutually exclusive ways to specify location, the description should say which inputs are needed and how they relate.

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 only 38% across 8 parameters, so the description is expected to compensate, and it says nothing about date, time, place vs. explicit coordinates, name, or timezone handling. The one anyOf alternative between a place and a lat/long/timezone triple — the main invocation ambiguity — is never mentioned.

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 names a specific analysis target (sibling bonds and speech/communication with kin) and the exact rule cards and source books it draws on, which clearly separates it from generic siblings like analyze_house or analyze_chart_topic. It is dense with domain jargon, but the verb+resource is unambiguous.

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: an agent can infer it should call this for questions about siblings or speaking with relatives. There is no explicit when-to-use, no prerequisites, and no named alternative among the many analyze_* siblings, so the routing burden is left to inference.

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