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 without the description. The description adds useful output-shape context (pillars involved, resulting element) and the metadata block discloses a 10-credit cost, but it says nothing about authentication, whether a full birth time/location is needed for meaningful results, or any limits on the interaction set.

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 front-loads the enumerated interaction types, and the bracketed metadata (group, endpoint, required param, credit cost) is compact and scannable. No filler, though the metadata lines are boilerplate shared across the whole BaZi family.

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 not be explained, and the description correctly sketches what comes back. However, for a 14-parameter tool with 29% schema coverage and a single required parameter, the description leaves the agent without enough to know which optional inputs change the result or how this relates to its many BaZi siblings.

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 only 29% across 14 parameters, so the description should carry the burden — and it explains none of them. It never clarifies why time, timezone, longitude, gender, dayBoundary, stageSchool, trueSolarTime, includeLuck or includeFullTable matter for an interactions lookup, nor does it reconcile 'present in the chart' with a schema whose only required input is a date.

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 the specific content the tool computes — stem combinations, six harmonies, full and half trines, clashes, harms, punishments, self-punishments — plus the pillars involved and the element a combination produces. That is far more informative than the title 'Branch and stem interactions'. It stops short of differentiating itself from sibling BaZi tools (bazi_chart, bazi_four_pillars, bazi_hidden_stems), so it does not reach a 5.

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?

There is no when-to-use or when-not-to-use guidance. An agent cannot tell from the description whether this should be called alongside astroway_bazi_chart or astroway_bazi_four_pillars, or whether the chart is derived internally from the single required date. The credit-cost note is metadata, not routing guidance.

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