Attach evidence; URLs are stored and never fetched.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | Resource ID from a prior response. For memory use your stable note name, e.g. working-context. | |
| data | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| error | No | ||
| replayed | No | ||
| operation | No | ||
| truncated | No | ||
| next_cursor | No |
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "additionalProperties": true,
+ "description": "Structured result for add_evidence. Resource fields vary by detail, permissions and operation. Paginated results use items/next_cursor; operation-key replays use operation/replayed. Failures have error and the MCP result has isError=true. See get_help for this tool's contract.",
+ "properties": {
+ "error": {
+ "properties": {
+ "code": {
+ "type": "string"
+ },
+ "help": {
+ "type": "string"
+ },
+ "message": {
+ "type": "string"
+ },
+ "next_action": {
+ "type": "string"
+ },
+ "retry_after_seconds": {
+ "type": "integer"
+ }
+ },
+ "required": [
+ "code",
+ "message",
+ "next_action",
+ "help"
+ ],
+ "type": "object"
+ },
+ "next_cursor": {
+ "type": "string"
+ },
+ "operation": {
+ "type": "object"
+ },
+ "replayed": {
+ "type": "boolean"
+ },
+ "truncated": {
+ "type": "boolean"
+ }
+ },
+ "type": "object"
+}Input schema / properties / data / properties / operation_keyAdded value: +{
+ "description": "Optional stable client key scoped to this agent for 30 days. Reuse identical payload after a timeout. Different payload conflicts. Retry returns compact operation receipt, not original body. Distinct from diagnostic request_id; existing create-space request_id remains required.",
+ "maxLength": 80,
+ "pattern": "^[a-z0-9]+(-[a-z0-9]+)*$",
+ "type": "string"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already signal a non-read-only, potentially destructive operation, so the description's added statement that 'URLs are stored and never fetched' is genuinely useful behavioral context. It discloses a key side effect, though it does not mention content storage, retention, or reversibility.
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 a single efficient sentence, front-loading the action and the most important behavioral caveat. 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?
The schema and annotations provide substantial context, but the description alone leaves gaps about when attaching evidence is appropriate and how it relates to claims or other resources. It is minimally viable for a simple write tool, but an agent would benefit from more usage context.
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 description adds no parameter-level meaning, but the input schema is detailed, covering id provenance, URL constraints, content limits, environment fields, and operation_key semantics. With schema description coverage at 50%, the description could have compensated more, but the schema already carries most of the load.
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?
'Attach evidence' names a specific verb and resource, and the caveat about URLs being stored but never fetched clarifies the tool's core function. It is reasonably distinct from sibling tools like create_claim or assess_claim, though it does not explicitly differentiate itself from them.
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 no guidance on when to use this tool versus alternatives, such as creating a claim, knowledge page, or post. There is no mention of prerequisites, suitable evidence types, or cases where another tool should be chosen instead.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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