PPN Hub — public APIs over MCP

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

With no annotations, the description compensates by disclosing key behaviors: it fans out to multiple APIs, returns merged JSON, handles partial results with an errors[] list, and requires authorization. This is substantial transparency, though it omits details like rate limits or latency.

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 very concise with three sentences, each adding essential information: behavior, error handling, and authentication. No redundant or vague phrasing.

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 lack of output schema and annotations, the description covers the main functionality and error reporting, but does not describe the structure of the merged JSON output or any constraints on usage, leaving some aspects incomplete for an agent.

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% and descriptions in the schema already explain lat, lon, and place adequately. The tool description adds no new semantic information beyond what the schema provides, so the default score of 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 clearly states it provides an 'Environmental brief for one location' by aggregating multiple APIs, and the name 'environment_brief' reinforces this. It distinguishes from the broader sibling tools 'execute_api' and 'search_apis' by being specialized and self-contained.

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 mentions it requires a specific authorization token, but does not explicitly state when to use this tool versus alternatives, nor provides any exclusion criteria. Usage is implied for environmental data retrieval but lacks explicit 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?

No annotations are provided, so the description carries the full burden. It only discloses an authentication requirement ('Authorization: Bearer ppn_live_*'). It does not disclose whether the tool is read-only or destructive, nor any rate limits, idempotency, or side effects. For a generic API executor that could perform mutations, this is a significant gap.

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 sentences, front-loaded with the purpose, and includes a critical prerequisite in the second sentence. No redundant 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?

Given no output schema and no annotations, the description is moderately complete. It covers the prerequisite and auth, but lacks explanation of return values (response body, status codes) and potential destructive nature. For a tool with 4 parameters and nested objects, it stays minimal.

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 the baseline is 3. The description adds minimal extra meaning beyond the schema: it relates 'api' and 'operationId' to the prerequisite search step. It does not explain 'body' or 'params' further, but the schema already provides adequate descriptions.

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 the tool executes a request against any of the 69 registered APIs, using a specific verb and resource. It distinguishes from the sibling tool 'search_apis' by directing users to use it first.

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 provides explicit guidance to use 'search_apis' first to find the correct api name and operationId, establishing a clear prerequisite. It does not explicitly state when not to use the tool, but the context implies it should only be used after identifying the API.

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 burden. It discloses behavioral traits beyond the schema: results carry a coverage field for region-limited APIs, region filter behavior (returns region-specific + global APIs, excludes other regions). This adds meaningful behavioral context. A small deduction because it doesn't disclose pagination behavior or output size limits beyond the limit param.

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 purpose and scope. The first sentence packs important info (450 endpoints, 69 APIs, return fields) efficiently. Second sentence adds practical usage guidance. Slightly dense but 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?

The tool is complex (6 params, 450 endpoints, discovery purpose) but the description covers the core use case, return content, region-specific behavior, and relationship to execute_api. No output schema means the description's note about 'returns matching endpoints with method, path, summary, parameters, and a ready-to-run example' compensates well. Minor gaps: no pagination or default ordering guidance, but adequate for a discovery 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 6 parameters are well-documented in the schema itself. The description adds marginal value by explaining the coverage field relationship to the region filter and listing domains/APIs in prose, but these largely overlap with schema descriptions for the individual params.

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?

Clear verb+resource: 'Search across 450 endpoints in 69 APIs.' It states what it returns (matching endpoints with method, path, summary, parameters, ready-to-run example) and its role as a discovery tool. It also distinguishes from siblings by explicitly calling out use before executing execute_api.

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 states when to use this tool: 'Use this to discover available API endpoints before calling execute_api.' This directly addresses the when-not/alternative distinction relative to the execute_api sibling. Additional context about the coverage field and region filter provides clear usage direction.

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