Send email from agents@x711.io via Resend. Costs $0.05 USDC per send. Requires an API key with credits. Limit: 10 emails/agent/day. Returns: { sent: true, message_id, to, subject }.
| Name | Required | Description | Default |
|---|---|---|---|
| to | Yes | Recipient email address. | |
| body | Yes | Plain-text email body. Max 8000 chars. | |
| html | No | Optional HTML body (overrides plain text in HTML clients). | |
| subject | Yes | Email subject line. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate a mutating operation (readOnlyHint=false), but the description adds valuable behavioral details: cost per send, USDC denomination, API key requirement with credits, daily rate limit, and the exact return format. This goes beyond the annotations and gives the agent a clear picture of side effects and constraints.
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 three sentences, front-loaded with the primary purpose, followed by cost, prerequisites, limit, and return value. Every sentence carries meaningful information with no redundancy or fluff.
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 tool's moderate complexity (4 params, no output schema, no enums), the description covers the key operational context: cost, authentication, rate limit, and return structure. It could mention failure scenarios or error handling, but the provided details are sufficient for an agent to use the tool safely and effectively.
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 each parameter (to, subject, body, html) has a clear description. The tool description adds no additional parameter semantics beyond what the schema already provides, so a baseline 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 the action ('Send email'), specifies the from address ('agents@x711.io'), and the provider ('via Resend'). This is a specific verb+resource combination that distinguishes it from all sibling tools, none of which are email-related.
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 context about cost, API key requirement, and daily limit, which implies when the tool can be used, but it does not explicitly state alternatives or when not to use this tool. No sibling tool is an email sender, so differentiation is less critical, but explicit usage guidance is still missing.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Several tools overlap in purpose: x711_web_search and x711_deep_search both search the web, x711_agent_see and x711_data_retrieval both fetch URL content, and x711_agent_ping and x711_agent_telegram both enable agent messaging. The detailed descriptions help, but the sheer number of tools and overlapping boundaries create confusion.
All tools share the x711_ prefix and use snake_case, but the name structure is inconsistent. Some follow verb_noun (x711_web_search, x711_email_send, x711_vault_query), while others are noun_verb (x711_tx_simulate, x711_x402_parse) or noun_noun (x711_data_retrieval, x711_genesis_forge). Related tools are grouped by prefixes (hive_, ping_shield_, substrate_), but overall the pattern is not uniform.
47 tools is far above the typical well-scoped range. While the server is positioned as a 'universal gas station' covering many domains, the sheer number makes it heavy and difficult to navigate, with many niche tools (substrate, ping shields) that could be consolidated.
Despite the large tool count, there are significant lifecycle gaps. Vault has write/query/compress but no delete; ping shield lacks an explicit unsubscribe; strategy tools only cover publish/fork; and there is no agent management (list/update/delete). Core CRUD operations are missing for several entities, which will cause agent failures.