lob_list_postcardsList sent/scheduled postcards, newest first. Lob API: GET /v1/postcards.
| Name | Required | Description | Default |
|---|---|---|---|
| after | No | Cursor for the next page (from a previous response's next_url). | |
| limit | No | Max results per page (1–100). Default 10. | |
| before | No | Cursor for the previous page (from a previous response's previous_url). |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare readOnlyHint=true, indicating a safe read operation. The description adds ordering detail ('newest first') and the API endpoint, enhancing transparency beyond the annotations.
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, highly efficient, and includes the API endpoint for debugging. Every word earns its place without 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 list tool with three optional parameters and no output schema, the description is sufficient. It covers the key behavior (listing, ordering, API base) but could optionally mention response format.
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%, with the schema already describing all three parameters (after, limit, before). The description adds no additional parameter semantics beyond this.
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 verb 'List' and the resource 'sent/scheduled postcards', and specifies the order 'newest first'. This distinguishes it from siblings like lob_create_postcard and lob_cancel_postcard.
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?
No explicit guidance on when to use this tool versus other list tools (e.g., lob_list_letters). The resource is clear, but the description does not provide exclusion criteria or alternative suggestions.
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.
Every tool targets a distinct resource and action, with clear verb-noun names like create_address and verify_us_address. There is no overlapping functionality, and even similar operations (e.g., list for different resources) are distinct.
All tools share the 'lob_' prefix and follow a consistent verb_noun pattern (e.g., create_postcard, list_letters, verify_intl_address). Multi-word nouns use underscores, maintaining uniformity throughout.
With 18 tools, the set covers the primary mail fulfillment operations—address management, postcards, letters, checks, self-mailers, and address verification—without feeling bloated or sparse. The count is well-suited to the domain.
The tool set has notable gaps: no create_check or create_self_mailer, no cancel for letters or checks despite being referenced, no update/delete for addresses, and only list for templates. These missing operations will likely cause agent failures in common workflows.