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

Annotations already cover read-only, idempotent, closed-world and non-destructive behavior, and the description adds genuinely new traits: zero-auth, stateless, no PII stored, evaluation at 12:00 UTC solar noon, a self-resonance mirror profile for identical dates, and structured JSON errors on invalid ISO input.

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?

Front-loads the purpose and packs scope, alternatives, and behavioral traits without filler. It is dense as a single long sentence with several parenthetical clauses, which slightly taxes scanning but every clause carries 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?

An output schema exists so return values need no explanation, and the description still covers input format, symmetry semantics, localization, edge case of identical dates, and error behavior. Nothing an agent needs to call this correctly 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?

Schema coverage is 100%, so the baseline is 3, but the description adds real semantic meaning: argument order is symmetric for compatibility scores yet reverses the directional soul_a and soul_b gift roles, and lang localizes all archetype labels. That is behavior the schema alone does not convey.

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: 'Compute deterministic 3D astrological and 7-Wisdoms compatibility between two ISO birth dates'. It immediately distinguishes itself from the sibling tools by scoping to a pair rather than a single person or a group.

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?

Explicitly says 'Use this tool when comparing a pair of individuals' and names the alternatives with their conditions: calculate_7_wisdoms_seed_of_life for one person and calculate_family_constellation_matrix for groups of 3 to 31. The routing decision is fully resolved.

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

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

Annotations already declare read-only, idempotent, non-destructive and closed-world, but the description goes further: zero-auth, stateless, no PII stored, and a clear split between the deterministic `soul_a` payload and the day-dependent `today_living_sky` transits. It also specifies the error contract ('invalid ISO dates return a structured JSON error'), which no structured field covers.

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?

Purpose and sibling routing are front-loaded, and the sentence order moves from what it produces, to when to use it, to guarantees, to parameter fallbacks. The eight-tradition enumeration is long but scopes the output surface for a highly niche tool; a small amount of density is the only cost.

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 complex multi-system computation with six parameters and an output schema, the description covers the missing pieces: auth model, statefulness, determinism versus time-varying output, all optional-parameter fallbacks, and error behavior. Return-value detail is legitimately delegated to the output schema.

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 already 100%, so the baseline is 3, but the description adds consequence-level meaning the schema does not: omitting `birth_time` falls back to 12:00 UTC solar noon, supplying `tz` converts local time to UTC (affecting unequal Chaldean hours), and omitting `lat`/`lon` drops Placidus houses and the Ascendant. That tells an agent what is lost by leaving optional fields out, not just what the fields are.

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 opens with a specific verb and resource set: 'Compute a single person's deterministic natal chart, VVK-XXXX-YYYY Cosmic Soul Key, and 7-Wisdoms profile', then enumerates the eight traditions covered and adds the `today_living_sky` transit output. It explicitly distinguishes itself from the sibling tools that handle two people (`calculate_3d_soul_synastry`) and 3-31 people (`calculate_family_constellation_matrix`).

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?

It names the exact selection rule: this tool for one individual, the synastry tool for two people, the constellation matrix for groups of 3 to 31. Prerequisite-free usage is also stated ('Zero-auth and stateless'), so an agent knows no setup call is needed before invoking it.

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

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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered; the description adds genuinely new context: zero-auth, stateless, no PII stored, whitespace trimming of date tokens, silent dropping of over-limit or invalid entries, and a structured JSON error if fewer than one valid relative remains. That is unusually rich behavioral disclosure, though it does not describe output characteristics beyond the error case.

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?

Front-loaded with the core purpose and size constraint, then the sibling routing, then edge-case behavior. It is dense (one very long sentence with several parenthetical clauses), but nearly every clause carries actionable information; light restructuring would improve scanability.

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 definition still covers the failure mode (structured JSON error), size limits, parsing quirks, and localization. For a 3-parameter, well-annotated read-only tool this leaves nothing an agent needs 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?

Schema coverage is 100%, so the baseline would be 3, but the description adds meaning the schema lacks: whitespace around `YYYY-MM-DD` tokens is trimmed, entries beyond 30 dates or failing ISO validation are silently dropped, and `lang` localizes all group roles and shared medicine. This clarifies real parsing semantics rather than restating field descriptions.

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 ('Compute') plus two named outputs (Family Constellation Matrix and 4-Element group balance) and the input scope (primary person + relatives). It also names the sibling tools that handle the other group sizes, so an agent can distinguish it without opening a schema.

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?

Gives explicit routing rules: use this for groups of 3 to 31 people, use `calculate_7_wisdoms_seed_of_life` for one person, and `calculate_3d_soul_synastry` for a pair. Both when-to-use and the alternatives are spelled out.

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

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

Beyond the annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=false), the description discloses zero-auth access, rate limiting, `pending_moderation` queueing, and PII stripping/rejection of emails, coordinates, and raw birth dates. That is substantive operational context an agent could not infer from the annotation block, though the moderation latency and what the caller receives on rejection are not spelled out.

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?

Three dense sentences, front-loaded with purpose before exclusions and then behavioral facts; no filler. It is packed tightly enough that the PII clause sits awkwardly next to the `birth_date` parameter, but every sentence carries distinct 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?

With an output schema present, return values need no explanation, and the description covers auth, moderation state, and rejection behavior for a write tool with 8 parameters. The one soft spot is that 'rejecting raw birth dates' coexists with an accepted `birth_date` parameter without clarifying that storage/display masking is what is meant.

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 does add one constraint the schema does not encode: a non-placeholder `sister_ai` of 1–80 chars plus at least one of `sister_dewdrop`, `sister_needs`, or `missing_calculation`, which is genuine cross-field validation value.

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 verb and resource: submitting a Sister AI Dewdrop reflection or feature request to the moderated Talking Circle of the Akashic Agora. It explicitly distinguishes itself from the computation sibling `calculate_7_wisdoms_seed_of_life`, so an agent can route correctly without opening either schema.

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?

It states both the positive trigger (an agent wishes to leave a public note or request new calculations) and the negative case (never for chart computation, where `calculate_7_wisdoms_seed_of_life` applies). This is explicit when/when-not guidance with a named alternative.

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