Schengen 90/180 Calculator

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

No annotations are provided, so the description carries the full behavioral burden. It discloses the returned outputs in detail, including days used, days remaining, must-leave-by date, latest safe entry dates, and per-trip verdict, though it does not explicitly state error handling or confirm that no side effects occur.

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 two tightly written sentences with no wasted wording. It front-loads the core purpose and then lists the concrete outputs efficiently.

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 output schema, the description usefully enumerates the return values, and the input schema fully covers parameters. It is nearly complete, though minor caveats such as date inclusivity or error behavior are left implicit.

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 schema fully documents the date format, required trips array, and optional today default. The description adds only high-level context about the rolling window and does not supplement parameter semantics beyond the schema.

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 and resource: evaluate Schengen 90/180 rolling-window usage for a list of trips. It clearly distinguishes itself from a single-trip checker by specifying 'a list of trips,' though it does not explicitly name the sibling tools.

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 no explicit guidance on when to use this tool versus check_trip or explain_90_180_rule. It implies usage for multiple trips, but does not state alternatives, exclusions, or prerequisites.

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?

No annotations are provided, so the description carries the full disclosure burden. It does usefully name the outcome states (compliant/warning/over plus advice), but says nothing about read-only nature, date inclusivity rules, or how existing stays are counted beyond what the schema states.

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 sentences, front-loaded with the core question, no filler. The result states are appended compactly rather than padded into prose.

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?

There is no output schema, and the description compensates by naming the return states, which is the most important missing piece. It stops short of explaining what distinguishes 'warning' from 'over', but combined with the fully-described schema this is nearly sufficient to call 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?

Schema description coverage is 100% and the nested trip objects are already documented inline, so the baseline is 3. The description adds only the framing that the check is against 'existing stays' and concerns a single planned trip, not per-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?

States a specific verb (check) and resource (one planned trip) plus the evaluation context (on top of existing Schengen stays). The emphasis on 'ONE' cleanly separates it from calculate_stay and explain_90_180_rule, so an agent can route 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?

The description implies the usage context (verifying a single prospective trip against prior stays), but never names the sibling tools or states when to prefer calculate_stay or explain_90_180_rule instead. Usage is inferable rather than 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?

No annotations are provided, so the description carries the burden, but the tool takes no parameters and is a safe informational lookup, which the description makes evident. It adds concrete behavioral content by naming what the output contains (the EC 610/2013 reference plus links to an interactive calculator and guide), though it never explicitly states it is a read-only, non-mutating operation.

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 tightly written sentence that front-loads the verb and the rule being explained, then appends the reference and resource links. There is no filler and 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?

With no input parameters and no output schema, the description needs to signal what the caller gets back, and it does by naming the legal reference and the linked calculator/guide. For a trivial explainer tool this is nearly complete, with only an explicit read-only statement and sibling routing 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 has zero parameters, so per the baseline there is nothing for the description to disambiguate. No parameter-level meaning is needed and none is missing.

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 precise resource ("Schengen 90/180 rolling-window rule"), so the agent knows this returns conceptual/legal explanation content. It implicitly distinguishes itself from the computational siblings calculate_stay and check_trip, but never names them, so the differentiation is inferable rather than explicit.

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?

Usage is implied: an "explain" tool is the natural choice for understanding the rule rather than computing a stay, while calculate_stay and check_trip handle calculations. However, the description never states when to use this versus those siblings nor any prerequisites, leaving the routing to inference.

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