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

Annotations already indicate readOnlyHint, idempotentHint, and non-destructive behavior. The description adds valuable behavioral detail beyond that: 'Use only facts explicitly supplied by the user; never infer or default missing compliance facts' and 'Pass omissions through so the deterministic engine can return INSUFFICIENT_INPUT.' It also discloses that the tool returns an evidence-linked decision, complementing the structured annotations well.

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 four sentences, front-loaded with the core purpose and then covering usage, behavioral constraints, and output. Every sentence earns its place with no filler or redundant restatement of the tool name.

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?

Given the output schema exists, the description need not detail return values, and it covers usage scenarios, omission behavior, and decision/next-action output adequately. The main gap is no explicit 'not for' boundary or sample payload shape, but the description is still sufficient for an agent to select and invoke the tool correctly.

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?

With schema_description_coverage at 0% and a single opaque 'payload' object, the description must compensate, and it partially does. It explains that the payload contains only user-supplied facts, lists applicable change categories, and gives an example missing compliance fact (same_salary_option_still_met). It stops short of a full payload schema, but for a deliberately flexible payload this is substantive guidance.

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: 'Check whether a specific employee/company change affects UK Skilled Worker sponsor duties.' It then enumerates concrete change types (salary, role, work-location, TUPE, merger, etc.), which clearly distinguishes it from siblings like licensing_source_status and list_supported_change_events.

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 an explicit 'Use for' list covering the relevant change scenarios, and it also says to pass omissions through rather than infer defaults. It does not name alternative tools for when-not/exclusion scenarios, so it has clear context but no explicit sibling 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?

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is well covered. The description adds that this is a status check of source evidence, but does not disclose additional behavioral details like caching, update frequency, or response characteristics. This is acceptable for a simple read-only status tool, so a mid-range score is appropriate.

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, well-structured sentence that immediately states the action and the object being checked. Every word contributes meaning, and there is no redundant phrasing or filler.

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 zero-parameter, read-only status-check tool with an output schema and comprehensive annotations, the description is complete. It tells the agent what is being checked and why it matters, and no additional invocation guidance 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 there is little for the description to add beyond what the schema already communicates. The baseline for zero-parameter tools is 4, and the description correctly focuses on the tool's purpose rather than inventing unnecessary parameter detail.

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 ('Check') and a specific resource: the freshness and review status of official GOV.UK evidence used by the sponsor-change checker. This is clearly distinct from the sibling tools, which cover impact assessment, event listing, and checker information.

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 purpose is clear enough that an agent can infer when to use it: when checking whether the underlying source evidence is fresh or has been reviewed. It does not explicitly name alternatives or exclusion conditions, but the wording 'used by the sponsor-change checker' provides sufficient context for selection among the given siblings.

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, idempotentHint=true, and destructiveHint=false, so the safety profile is covered without description help. The description adds the scoping detail that this list concerns events assessable under Skilled Worker sponsor duties, but no additional behavioral traits such as sorting, filtering, or result size are disclosed.

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 sentence that immediately states the action and scope. Every word contributes meaning, and there is no redundant restatement of the tool name or annotations.

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 zero-parameter, read-only listing tool with an output schema available, the description is sufficiently complete. An agent can determine what the tool returns, and the output schema handles return-value details. No critical invocation information 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?

There are zero parameters, so the schema carries no parameter semantics to clarify. With 100% schema coverage and an empty parameter object, the description does not need to compensate for any missing parameter information. Baseline 4 applies for a no-parameter tool.

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 a specific verb ('List') and a precise resource ('sponsor-change event types this checker can assess for Skilled Worker sponsor duties'). This clearly differentiates the tool from siblings like assess_change_impact, licensing_source_status, and sponsor_change_checker_info, which involve assessment, status, and general info respectively.

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 the tool should be used when an agent needs to know which sponsor-change event types the checker supports. However, it does not explicitly mention when not to use it or point to an alternative such as assess_change_impact for actually evaluating a specific event. Usage context is implied but not stated.

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, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered. The description adds context that the tool explains scope and supported decision states, which is useful but does not go beyond what annotations already provide. No contradiction with 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, clear sentence that front-loads the tool's purpose. It is appropriately sized for a zero-parameter informational tool, though it could be slightly more specific about the decision states it covers.

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?

Given the tool has no parameters, an output schema exists, and annotations cover safety, the description is largely complete. It explains the tool's scope and purpose, which is sufficient for an agent to decide whether to call it. A minor gap is that it doesn't enumerate the supported decision states, but the output schema likely covers that.

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 schema is trivially complete. The description correctly focuses on the tool's informational purpose rather than parameter details. Baseline 4 is appropriate for a zero-parameter tool.

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 ('Explain') and a clear resource ('UK Skilled Worker sponsor-change checker scope and supported decision states'). It distinguishes itself from sibling tools like assess_change_impact and list_supported_change_events by focusing on explaining the checker's scope and decision states rather than performing an assessment or listing events. However, it could be slightly more explicit about what the tool does not do.

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 the tool is for understanding the checker's scope and decision states, which suggests it should be used when an agent needs background information before using assess_change_impact or list_supported_change_events. However, it does not explicitly state when to use this tool versus its siblings, nor does it provide 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.