NythosX Agent Tools

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

With no annotations, the description carries the full burden and does well: it discloses the monetary cost model ($0.005 USDC per call via x402) and the return composition (sorted ranking, cheapest chain, chains that could not be queried). It stops short of stating failure modes or whether the x402 payment is required upfront.

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 motivating question, then a compact sentence covering operation, inputs, and return, ending with pricing. No wasted clauses, though the leading question is slightly verbose next to the denser second sentence.

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 2-param read tool with no output schema and no annotations, the description covers the essentials: what it computes, the return shape, and the cost. Missing only minor details like supported chain coverage or latency, which an agent can tolerate.

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 both parameters are enums, so the schema already documents valid values. The description restates the enum sets (transfer/usdc_transfer/swap and slow/standard/fast) without adding semantics such as what distinguishes tiers in practice. Baseline 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 names a specific action (ranks chains by USD cost) and resource (transaction types across chains/speed tiers), and the opening question makes the intent unambiguous. It does not explicitly differentiate itself from the sibling get_gas_price, so the agent must infer that this tool compares across chains rather than fetching a single price.

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?

"Where is it cheapest to send this transaction right now?" implies the use case (cost-comparison before sending) but offers no explicit when-to-use vs. when-not, and never mentions get_gas_price as the single-chain alternative. The framing is helpful context rather than routing 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?

With no annotations, the description carries the full burden and does well: it discloses data freshness ('Updated every 15 seconds'), a concrete per-call charge ('$0.002 USDC per call (x402)'), and the shape of the payload (slow/standard/fast tiers, USD cost of transfer, USDC transfer and swap). It still omits payment/auth mechanics for x402 and any error or rate-limit behavior.

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-loads the core purpose and stays short, but the opening sentence is essentially repeated by the second sentence ('Current gas and fee prices for one chain.' vs. 'Current gas and fee prices for Base, Ethereum, ...'), so one sentence does not fully earn 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?

There is no output schema, so the description rightly describes the returned content (tiers plus USD transfer/swap costs) and adds freshness and cost context. Enough for an agent to call correctly, though payment/auth handling for the x402 charge is unaddressed.

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 'chain' parameter is fully documented with an enum. The description restates the chain list but adds no format, default, or constraint detail beyond what the schema already provides, so the baseline of 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 ('Current gas and fee prices') and narrows scope with 'for one chain', which implicitly separates it from the compare_gas_costs sibling. It never names that sibling explicitly, so the differentiation is left to inference rather than stated.

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 only implied: query a single chain when you need live gas tiers and transfer costs. No when-to-use / when-not-to-use guidance and no pointer to compare_gas_costs for multi-chain needs, which is the obvious alternative among 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?

With no annotations, the description carries the full burden, and it does disclose the cost profile ('free') and the content returned. Gaps remain (no auth/rate-limit/return-format notes), but for a zero-parameter read-only listing tool the risk surface is minimal.

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 front-loaded sentence: the action and its main output come first, with the enumerated chains and constants as trailing detail. 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?

No output schema exists, so the description must convey return content, and it does so by naming the chains and the gas-unit constants. Minor gaps (exact shape of the constant values, whether the list is chain-filtered) keep it short of a 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?

The schema has zero parameters, so there is nothing for the description to disambiguate; baseline 4 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?

Specific verb+resource ('List supported chains') with an explicit enumeration of the six chains and the additional payload (gas-unit constants). It does not name or differentiate from siblings like get_gas_price or compare_gas_costs, so it is clear but not sibling-aware.

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 parenthetical '(free)' and the note that the constants are 'used by the paid tools' imply this is a lookup/discovery call to run before the paid gas tools, but no explicit when/when-not or alternative is 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?

With no annotations, the description carries the full behavioral burden and does so well: robots.txt compliance, private-host blocking, a five-redirect cap, a 3 MB page cap, and a per-call price of $0.003 USDC (x402) with payment implied. That is exactly the operational context an agent needs before invoking a metered network fetcher.

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 purpose before constraints. The enumeration of returned fields is slightly list-like but each clause carries real information; nothing is 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?

With no output schema, the description compensates by naming the returned fields (title, byline, site name, excerpt, word count, body) and the operational limits. It does not describe failure modes such as robots.txt disallow, non-HTML content, or fetch errors, which is a minor remaining gap.

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 both parameters are already documented in the schema, including the 200-link cap. The description's mention of links=true largely restates the schema and adds no new syntax, format, or edge-case meaning, 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 and resource ('Convert any web page into clean, readable Markdown'), then adds the mechanism ('Fetches a public web page and returns clean Markdown'). It is unambiguous and clearly distinct from the gas-price siblings, which share no domain overlap.

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 a clear intended use ('give an AI agent readable text from a URL without writing your own scraper') and the key invocation trigger (links=true for outbound links). It stops short of stating when not to use it or naming alternatives, but the sibling tools are in an unrelated domain so there is little to disambiguate against.

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