money4k-split-bill

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

Annotations declare the safety profile (readOnly=false, idempotent=false, openWorld=true, destructive=false), and the description still adds valuable operational context beyond them: OAuth requirement, no profile lookup needed, the fact that anyone with the returned share_url can view the bill, and the non-idempotency caveat about not blindly retrying after a timeout or ambiguous server error. It also discloses validation semantics (fixed control total, no invented taxes or adjustments) that annotations cannot express.

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, example and exclusions are front-loaded, but the body is a dense run-on that repeats rules already stated verbatim in the item unit_price and total_price schema descriptions (standalone tax items, not double-adding included taxes). Several clauses about reconciliation, tips and splits are useful, yet the sheer length and duplication make it harder to scan than it needs to be.

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 mutation tool with nested objects and an output schema, this covers everything an agent needs: currency handling, total reconciliation, tax allocation, tip and split rules, retry policy, and auth. Return values are already covered by the output schema, and the description still names share_url and the bill UI, so nothing material 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% with rich nested descriptions, so the baseline is 3, but the description goes further by showing how inputs map to fields concretely (pizza 1 x 20, beer 2 x 5, bill total EUR 30), by requiring positive quantities / nonnegative prices / a single currency, and by explaining that quantity encodes participant count for shares and tips. It largely restates the schema's tax and total rules, which caps it at 4 rather than 5.

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 first sentence gives a specific verb+resource+outcome: create and share an itemized bill with a participant-selectable link. It also names the sibling it is not (update_bill), so an agent can separate it from update_bill, set_bill_selections_batch and get_current_user_profile without opening any 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?

Explicit when-to-use (bill creation for a meal or shared purchase, from photo, typed list or prose) and explicit when-not (reading a receipt, simple arithmetic, collecting payments, booking a restaurant), plus the named alternative for edits. Nothing about tool selection 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.

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint; the description adds genuinely new context by specifying it requires OAuth and derives identity from the bearer token. That auth requirement is not encoded in the annotations, so it earns credit, though nothing is said about failure modes (e.g., missing/expired token).

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 tight sentences with zero filler, and the payload is front-loaded. The final sentence ('read-only helper... for calls from the app UI') partially restates what readOnlyHint already conveys, a minor redundancy.

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 and full annotation coverage, the description only needs to supply identity/auth and intent context, which it does. Nothing an agent needs to call this zero-param tool 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?

The tool takes zero parameters, so the baseline is 4; there is no parameter syntax the description could or should document.

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 ('Returns the authenticated user's id, full_name, email and created_at') and enumerates the returned fields. It is clearly distinguishable from the sibling write tools (create_bill, update_bill, set_bill_selections_batch), which all mutate bill data.

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 clear context — it exists so the bill UI can identify the user's own selections — which is a usable 'when to use' signal. It does not name an alternative or an explicit 'when not to use' condition, so it falls short of a 5.

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?

Goes well beyond the annotations: quantity 0 clears a selection, omitted selections stay unchanged (concretising idempotentHint), selections and the display name are visible to anyone with the bill link (privacy disclosure), and OAuth is required. The only gap is that it doesn't describe error behaviour or what the response confirms, but annotations already cover the safety profile.

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 trigger condition and tightly packed, but slightly long and mildly redundant — the later 'cannot select on behalf of other people' restates the earlier 'do not select for friends'. Every other sentence earns its place.

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 covers trigger, exclusions, mutation semantics, visibility and auth. Nothing an agent needs to invoke 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 semantics the schema lacks: quantity 0 clears a selection, omitted selections remain unchanged, and IDs must be actual bill/item IDs. That is meaningful behavioural meaning for both parameters rather than a restatement.

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: saving absolute item-selection quantities for the connected user on an existing shared bill, explicitly scoped as affecting only that user's personal share. It is readily distinguishable from create_bill, update_bill and get_current_user_profile, and explicitly says it does not change bill items, prices or totals.

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 an explicit trigger (user asks to select, change or clear their own items on an existing shared bill) and explicit exclusions (not for creating/editing a bill, not for selecting for friends, not for marking payments completed). The alternatives are described functionally so an agent can route correctly without opening sibling schemas.

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?

The annotations declare destructiveHint=true and idempotentHint=false, and the description reinforces this with concrete destructive semantics: it 'Replaces the complete content' and 'omitted items and their selections are deleted,' plus a warning not to send a partial list. It also discloses auth needs ('Requires OAuth') and the return shape (updated bill and the same share_url), adding context well beyond what annotations convey.

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?

It is front-loaded correctly, opening with purpose and when-to-use before edge cases. However, it is very long and several statements restate rules already carried by the 100%-covered schema (item total equals unit_price times quantity, tax allocation, total reconciliation), and the instruction blocks stack without clear visual separation, diluting scannability.

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 destructive, multi-parameter mutation with nested objects, the description covers the full replacement model, ID semantics, currency constraints, tip/portion math, rounding-clarification behavior, and the returned share_url. With an output schema present it need not detail return values, and the remaining gaps for correct invocation are effectively closed.

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, but the description adds operational meaning beyond the schema: preserving existing item IDs vs. using an empty ID for new items, the rule that item total_price must equal unit_price times quantity, the bill-level reconciliation rules, and the tip/share-division procedures. Much of this complements rather than repeats the schema, though the tax and total-equality rules overlap with schema text.

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 (edit an existing shared bill) and enumerates the concrete edit types it supports: correcting items, renaming, add/remove purchases, tips by participant count, and dividing shared dishes. It also explicitly distinguishes itself from siblings by naming create_bill and set_bill_selections_batch and the cases they own. An agent can route correctly without reading any 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 gives an explicit when-to-use clause, an explicit when-not-to-use clause (new bill, hypothetical question, recording participant choices), and names the exact alternative tool for each excluded case. Nothing about tool selection 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.