lob_letters_getRetrieve a specific letter by its unique ID (ltr_…). Provide the letter identifier to get its details.
Retrieve a single letter by ID.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | Letter ID (`ltr_…`). |
Changes observed during successful MCP inspections.
v1.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description is consistent with annotations (readOnlyHint, etc.) but adds no extra behavioral context (e.g., error behavior, rate limits). Annotations already provide a clear safety profile.
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?
One sentence with no filler. Directly states the action and resource. Every word 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?
Adequate for a simple retrieval tool, but lacks mention of return value or error cases. With many siblings and no output schema, the description could hint at the response structure. Still minimally viable.
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 single parameter 'id' is fully covered by the schema (including pattern and description). The description adds no additional meaning beyond the schema, so 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 uses 'Retrieve' (specific verb) and 'letter by ID' (resource and method), clearly distinguishing from sibling tools like lob_letters_list or lob_letters_create.
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 guidance on when to use this tool versus alternatives (e.g., lob_letters_list, lob_letters_preview). The description does not specify context or exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.