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

Annotations already indicate readOnlyHint=false, idempotentHint=false, and destructiveHint=false. The description adds 'Add' which is consistent with a non-read-only, non-idempotent write operation, but it does not provide additional behavioral context beyond the annotations.

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?

The description is a single, concise sentence that clearly communicates the tool's function and purpose without any unnecessary words or digressions.

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?

The description fully covers the tool's primary purpose and the context of household expense splitting. While it does not mention edge cases or output details, the simplicity of the operation means the description is sufficiently complete.

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 schema provides descriptions for both parameters (name: 'Their name', also_called: 'Nicknames speech recognition might produce'). The description does not add extra meaning beyond the schema, so baseline score of 3 is appropriate given 100% schema coverage.

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 clearly states the specific action (Add) and the resource (someone to the household), along with the purpose (so expenses can be split with them). This distinguishes it from sibling tools like record_expense or show_balances.

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 implicitly conveys when to use this tool: when you need to add a person to the household for expense splitting. It does not explicitly mention alternatives, but the use case is specific enough that an agent can infer appropriate usage.

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=true and idempotentHint=true, establishing the safe read-only profile. The description adds the 'most recent first' ordering behavior, but does not disclose what kinds of records are included or how far back 'lately' reaches. There is no contradiction with the annotations.

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?

The description is a single efficient sentence that front-loads the verb and includes the key ordering constraint. There is no filler, repetition of the title, or extraneous content.

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 one-parameter read-only tool with annotations and an output schema, the description is mostly adequate. The main gap is that 'what was recorded lately' is ambiguous about scope—it does not specify whether this lists only expenses or all recorded household actions, so an agent may not know what results to expect.

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%, and the single parameter limit is fully documented with a description, default, minimum, and maximum. The description adds no parameter-level detail, but it does not need to because the schema already carries the meaning.

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 uses the specific verb 'List' and names the resource ('what was recorded lately'), and adds the ordering detail 'most recent first.' This is enough to separate it from siblings like show_balances and record_expense, though 'what was recorded' is slightly broad and could include expenses, settlements, or other household actions.

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?

No guidance is given about when to use this tool versus alternatives such as show_balances, what_do_i_owe, or undo_last. The recency framing implies a use case, but the description leaves the selection decision entirely to the agent with no exclusions or alternative routing.

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 flag non-read-only, non-idempotent, and non-destructive behavior, so the safety profile is covered. The description adds no side-effect detail such as altering household balances or interacting with undo_last, but it does clarify that the expense is on the household's behalf. Given the annotation coverage, this is adequate but thin.

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?

Two short sentences, front-loaded with the action and a direct usage trigger. Every word earns its place and there is no filler or repetition.

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 a rich output schema and fully documented parameters, the description does not need to explain return values or every field. The trigger condition plus schema-level idempotency guidance is enough for correct invocation. The only minor gap is silence on the effect on balances, but that does not block usage.

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 schema fully documents amount, paid_by, description, split_between, shares, and idempotency_key. The description only loosely mirrors these concepts ('someone paid for something') without adding format, constraint, or default details. The baseline of 3 is appropriate because the schema carries the parameter burden.

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 states a clear action and resource: record a payment made on the household's behalf. 'This is the main tool' signals it is the default expense-capture tool, which helps distinguish it from balance and activity siblings. It could be more explicit about not being for settlement or queries, but the core purpose 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?

The instruction 'use it the moment the user mentions paying' is an explicit trigger condition. No exclusions or alternative routing are provided, but the sibling set makes the write-vs-read distinction easy to infer. This meets the clear-context level, just without formal when-not guidance.

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 description only says 'record', which implies a write operation, but provides no details on side effects, idempotency, or whether balances are updated. Since annotations provide no hints (all false), the description carries the full burden but falls short.

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?

The description is a single, concise sentence that contains no unnecessary words. It is well-structured and easy to parse.

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?

The description is minimal and does not explain what 'settle up' entails in a larger expense-tracking context, such as whether it updates balances or creates a transaction. This ambiguity could confuse an agent, especially with several sibling tools that overlap in purpose.

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 description adds no additional meaning to the parameters; the schema already fully describes each parameter. With 100% schema coverage, the baseline is 3, and the description does not enhance it.

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 clearly states the tool's purpose: recording that one person paid another back. It is specific and distinct from sibling tools like record_expense, which handles shared expenses, making the tool's function 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?

No guidance is provided on when to use this tool versus alternatives such as record_expense or what_do_i_owe. The description offers no context for choosing this tool over others.

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 provide readOnlyHint=true and idempotentHint=true, so the description doesn't need to repeat that. It adds valuable context about the output scope (net positions and a minimal settlement plan), which goes beyond the annotations. No contradictions.

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, well-structured sentence that front-loads the core action ('Report every member's net position') and then adds a concise qualifier about the settlement plan. No wasted words.

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 no parameters, read-only/idempotent annotations, and an output schema present, the description sufficiently covers what the agent needs to invoke it correctly. The return format is likely covered by the output schema, so no additional explanation is needed.

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 has zero parameters, so the baseline of 4 applies. The description doesn't need to explain any parameters, and the schema confirms an empty argument list.

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 states a specific verb ('Report') and a clear resource ('every member's net position and the fewest payments that settle it'). It clearly distinguishes from siblings like 'what_do_i_owe', which likely targets an individual, whereas this covers all members.

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 phrase 'every member' implies a group-wide report, giving some context for when to use it. However, it does not explicitly state when to prefer this over alternatives like 'what_do_i_owe' for individual balances, nor does it mention any exclusions.

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 indicate readOnlyHint=false (mutation) and destructiveHint=false (not destructive). The description confirms it creates a new ledger and adds the speaker, adding the 'first member' detail beyond annotations. However, it does not disclose idempotency (what happens if called twice) or any error conditions, so it adds only modest context.

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?

The description is a single, concise sentence: 'Create a shared ledger and put the speaker in it as the first member.' It is front-loaded with the primary action and contains no fluff or redundant 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?

The tool has an output schema (so return values are covered elsewhere) and a clear action. The description fully explains what the tool does. It does not mention that this is typically the first step in using the household ledger or that calling it again might create another household, but these are inferable from the name and siblings. Overall, it is sufficiently complete for a creation tool.

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%: all three parameters (name, currency, your_name) have clear descriptions. The tool description does not add any parameter-specific meaning, but with full schema coverage, the baseline of 3 is appropriate.

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 states a specific verb ('Create') and resource ('shared ledger'), and clarifies that the speaker becomes the first member. This clearly differentiates it from sibling tools like record_expense, show_balances, etc., which handle other aspects of the ledger.

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 implies usage for initial setup by describing creation of a new ledger and adding the speaker, but it does not explicitly state when to use this tool versus alternatives like add_person, nor does it mention any exclusions (e.g., if a household already exists). Guidance is implied rather than explicit.

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 already flag destructiveHint=true, so the agent knows this is a destructive operation. The description reinforces that by saying it 'reverses' an entry. It does not explicitly state that only the most recent entry is affected (though that is implied by the name and description) or whether the undo itself can be undone, but this is a minor gap given the simplicity of the tool.

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?

The description is a single, concise sentence that states the action, the target, and a contextual trigger. There is no extraneous information, and the structure is clean and easy to parse. It fits the tool's simple nature perfectly.

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 simple undo operation, the description is complete. It tells what the tool does, when to use it, and (via annotations) that it is destructive. No output schema is provided, but that is acceptable given the tool's nature. An agent has enough context to decide when and how to invoke it without further clarification.

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 only parameter, idempotency_key, is fully described in the schema with a clear explanation: 'Repeat unchanged when resending; omit otherwise.' This is a standard idempotency key instruction and covers the parameter's purpose and usage. With 100% schema coverage and an accurate description, there is no ambiguity.

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 clearly states the tool's function: 'Reverse the most recent expense or payment.' The verb 'Reverse' and resource 'most recent expense or payment' are specific and unambiguous. It also stands apart from sibling tools like record_expense or settle_up by being the only undo operation, so an agent can easily distinguish it.

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 includes an explicit usage scenario: 'for when something was misheard.' This tells the agent when to invoke the tool (e.g., after an incorrect voice entry). However, it could more broadly state 'when an incorrect entry was made' and does not mention any limitations or prerequisites (e.g., that an undoable entry must exist), so it leaves a little room for interpretation.

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 and idempotentHint, and the description adds useful directional semantics: the amount is what the speaker owes another person, not what is owed to them. It also clarifies the default behavior when no person is named, which is genuinely useful beyond the structured annotations.

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?

Two tight sentences with no filler, and the core behavior is front-loaded before the usage example. Every 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?

For a simple optional-parameter query tool, the description plus annotations and output schema cover selection, invocation, and behavioral expectations. Nothing an agent needs to call it 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 input schema already documents the person parameter with 100% coverage, including that omitting it gives the overall position. The description reinforces this meaning but adds no new syntax, format, or edge-case detail beyond what the schema provides.

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 states a specific verb ('answer'), a precise resource (what the speaker owes), and scopes the behavior to one named person or the overall position when no one is named. The example 'how much do I owe Chris' makes its purpose unmistakable and distinguishes it from siblings like show_balances.

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 a clear usage context with an explicit example ('Use this for how much do I owe Chris') and explains the no-person case. It does not explicitly say when not to use it or name alternatives, so it stops 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.