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

No annotations, so the description carries the full burden. It usefully discloses that the check performs a real network request through the proxy (not a mock), which implies latency and network egress, but says nothing about failure semantics, whether it throws or returns a status, or what the result contains. This is meaningful but incomplete disclosure for a validation 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?

Two sentences, no filler. The core purpose and mechanism come first, with the when-to-use guidance following immediately.

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 and no annotations, the description should at least hint at what a successful/failed validation returns (boolean, latency, error detail). It covers inputs and usage well but leaves the result shape and failure behavior unstated, which is a real gap for a check 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%, so all three parameters (proxy, testUrl, timeoutMs) are already documented with defaults and constraints in the schema. The description's example URL format duplicates the schema rather than adding new semantics, so the baseline 3 applies.

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 (validates) and resource (single specific proxy), and explains the mechanism ('by making a real request through it to a target URL'). Example proxy URLs make the expected input format concrete and clearly distinguish it from find_proxy/list_proxies.

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 names two use cases — testing a proxy you already have, and re-checking a specific site through a proxy that find_proxy returned. The alternative tool is named and the selection condition is clear.

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?

With no annotations, the description carries the full burden and does reasonably well: it discloses concurrent batch testing against a target URL, that it returns the fastest working proxy plus backups, and (via forceRefresh/'cached proxy list') that a cache exists. It omits rate limits, timeout/failure behavior on no match, and whether network egress occurs, keeping it from a 5.

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 sentences, front-loaded with the core action, followed by mechanics, then usage condition. Every sentence adds distinct value with no 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?

For a 7-param tool with no output schema, the description covers purpose, selection behavior, and return shape ('fastest one that actually works, plus a few backups'). It lacks guidance on no-match outcomes and the cache's behavioral implications, minor gaps that keep it from 5.

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 already documents all 7 parameters with defaults and bounds. The description adds no syntax or format detail beyond what the schema provides, so baseline 3 applies.

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+resource ('Finds a live, validated free proxy') with scope ('optionally filtered by country and/or protocol') and contrasts implicitly with siblings like check_proxy or list_proxies by emphasizing validated-and-working selection. An agent can distinguish this as the search-and-validate tool.

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 concrete when-to-use guidance: 'when a direct request/curl is geo-blocked or otherwise failing and you need a working proxy to route through.' It does not name sibling alternatives (check_proxy vs list_proxies) to route away, 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?

No annotations are provided, so the description carries the full behavioral burden. It discloses the data source (merged proxy pool) and that results reflect currently covered countries, but says nothing about caching or freshness — the cache/refresh behavior is only visible in the forceRefresh parameter schema, not the description.

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, zero waste, with the core behavior front-loaded before the usage routing. Nothing is padded.

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?

Though there is no output schema, the description explains the return shape (countries with per-country proxy counts), which is what an agent needs. The only omission is the freshness/caching dimension that forceRefresh hints at.

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?

Only one parameter and schema description coverage is 100%, so the schema already documents forceRefresh fully. The description adds no information about the parameter, which is acceptable given the baseline for high 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?

States a specific verb and resource ('Lists the countries') plus the scope ('currently covered by the merged proxy pool') and the return shape (a proxy count per country). This clearly distinguishes it from find_proxy, check_proxy, and list_proxies.

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 routes the agent: use this to discover country codes worth passing to find_proxy 'before asking for one.' Names the alternative sibling and the ordering condition that selects 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?

No annotations are provided, so the description carries the burden, and it does well: it discloses that no live network testing occurs, that results are merged/deduped across sources, and that ordering is cache-first with previously confirmed-fast proxies prioritized. It does not cover result freshness/staleness beyond forceRefresh or any rate limits, leaving modest gaps.

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, zero filler, and the core behavior plus ordering rule is front-loaded before the routing hint. Every clause 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 read-only list tool with full schema coverage and no output schema, the description covers behavior, ordering, and sibling routing adequately. Only minor gaps remain, such as what a returned entry contains or how stale the cache can be.

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 all four parameters (limit, country, protocol, forceRefresh) are already documented in the schema. The description only echoes the country/protocol filtering, adding no format or interaction detail beyond what structured data provides. Baseline 3 applies.

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 ('Lists merged, deduped proxies from all sources') plus scope details (country/protocol filtering, cache-first ordering). An agent can distinguish it from find_proxy and check_proxy purely from the text.

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 names the alternative and the selecting condition: 'use find_proxy when you need a proxy that is actually confirmed working right now.' It also clarifies what this tool does not do (no live testing), which is the key routing signal.

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