headless-oracle

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

No annotations are provided, so the description carries the full burden. It discloses that the tool is not cryptographically signed, does not reflect real-time circuit breaker halts or KV overrides, is fail-closed, and has sub-100ms p95 latency. This is exceptional transparency beyond any structured metadata.

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 lengthy but well-structured with clear sections (WHEN TO USE, RETURNS, caveats, latency). It is front-loaded with the core purpose, and every sentence carries operational value, making the length justified.

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 no output schema, the RETURNS section enumerates all fields precisely. The tool's complexity (28 exchanges, holiday calendars, lunch breaks, special weekend patterns, crypto 24/7) is fully addressed, and fail-closed behavior is specified for safe agent use.

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 fully documents the sole parameter (mic) with an enum and description, achieving 100% coverage, so the baseline is 3. The tool description adds some context about 28 exchanges but does not enrich the parameter syntax or meaning beyond what the schema already 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 opens with a specific verb (Returns) and a clear resource (holiday-aware trading session schedule) scoped to 28 exchanges. It distinguishes from the sibling get_market_status by clarifying it provides schedule timestamps rather than signed status.

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?

An explicit 'WHEN TO USE' list enumerates concrete scenarios such as planning trade execution windows and checking holiday closures. It also explicitly directs users to get_market_status for authoritative signed status and notes what this tool does not reflect, providing clear exclusion criteria.

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 provided, the description fully carries the behavioral disclosure burden. It explains the signed receipt, 60-second TTL, fail-closed rule for UNKNOWN and HALTED, the requirement to not execute if the tool is unreachable, latency expectations, and the exact return fields. This is far beyond minimal disclosure.

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 front-loaded with the core purpose and uses clear labels, but it is overly verbose. Repetitive emphasis like 'Pre-trade safety check', 'USE AS', and 'This is not optional data' could be condensed. The extensive regulatory compliance details and model-agnostic framing add length without directly aiding tool selection or invocation.

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 there is no output schema, the description compensates by explicitly enumerating the return fields (receipt_id, mic, status, etc.) and behavioral semantics such as TTL, fail-closed rules, and the requirement to include attestation_ref in downstream flows. It also covers edge cases like expired receipts and unreachability, making the description genuinely complete for a safety-critical 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?

Although the schema already covers the single 'mic' parameter with 100% coverage, the description adds substantial value by listing all 28 exchange codes with their full exchange names, categorizing them (Equities, Derivatives, Crypto 24/7), and explaining the expected status values. It also clarifies that SMA means Signed Market Attestation, not Simple Moving Average, which prevents confusion.

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 that the tool returns an Ed25519-signed market-state receipt for pre-trade verification and pre-execution gating across 28 global exchanges. It uses a specific verb ('returns') and identifies the resource (market-state receipt), effectively distinguishing this from sibling tools like get_market_schedule and get_payment_options.

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 explicit usage guidance: call this BEFORE executing any trade, treat it as a safety gate, and halt execution if the status is not OPEN or the receipt is expired. It does not explicitly state when not to use the tool or name alternatives (though list_exchanges is referenced in the schema), so it misses the full 'when-not/alternatives' criterion.

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. It discloses 'No authentication required' and 'Always returns 200', which are valuable behavioral facts. It also mentions 'Model-agnostic' and lists the return keys, providing transparency about the response shape. No contradictions with annotations exist.

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 well-structured with labeled sections ('WHEN TO USE', 'RETURNS') and is informative without excessive verbosity. The 'Model-agnostic' sentence is a slight extra but still adds relevant context. Overall, 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 zero-parameter read-only endpoint, the description is quite complete. It covers purpose, usage timing, authentication behavior, HTTP status, and return keys. The lack of an output schema is mitigated by the detailed explanation of the upgrade ladder. It could be more precise about the exact format of the response, but this is sufficient for an agent to use 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?

The tool has zero parameters, so the baseline is 4. The description does not need to add parameter semantics, but it does explain the return object structure and provides concrete examples (e.g., sandbox, x402, credits), which adds context beyond the empty 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 clearly states 'Returns available payment and authentication options for accessing live market data', which is a specific verb+resource. It distinguishes itself from siblings like get_market_schedule and list_exchanges by focusing on payment/authentication rather than market data itself.

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 provides 'WHEN TO USE: when you need to understand how to authenticate or pay before making a request that requires a key or payment.' This gives clear usage context, though it does not mention when not to use or explicitly name alternatives. Still, the siblings are clearly different, so this is strong 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 of behavioral disclosure and does well: it states 'Pure static data, always returns 200, no authentication required, sub-50ms p95,' plus model-agnostic and compliance attributes. However, it claims to return 'market hours metadata' and 'exchange operating hours metadata,' yet the specified return schema only includes mic, name, timezone, and mic_type—no actual operating hours. This is a minor misrepresentation that prevents a perfect score.

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 well-structured and front-loaded with purpose and when-to-use guidance. However, it is verbose, listing all 28 exchanges with full names and codes, which is redundant given the tool returns that same data. Most sentences serve a purpose, but the exhaustive enumeration could be condensed without losing essential guidance.

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 no output schema, the description compensates by explicitly providing the return shape ({ exchanges: Array<{ mic, name, timezone, mic_type }> }) and operational constraints. It also gives a complete market coverage breakdown and performance expectations. The main gap is the inconsistency between the promised 'market hours metadata' and the actual returned fields, which could mislead an agent expecting schedule information.

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 0 parameters, so the baseline is 4. The description appropriately doesn't discuss inputs, as there are none. It correctly focuses on output and usage context, adding no misleading parameter information.

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 'Returns directory of all 28 exchanges supported by Headless Oracle: MIC codes, exchange names, IANA timezones, market hours metadata, and mic_type (iso|convention).' This clearly states the verb (returns), the resource (directory of exchanges), and the exact fields. It also distinguishes itself from siblings by explicitly framing itself as the discovery surface to use before get_market_status or get_market_schedule, so its unique role is obvious.

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 contains a dedicated 'WHEN TO USE' section: 'call once at agent startup to discover supported markets before calling get_market_status or get_market_schedule.' It names the alternative tools and provides concrete context for when this tool is the right choice, and hints at exclusions (not for status/schedule queries).

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