diff --git a/packages/dd-trace/src/log/index.js b/packages/dd-trace/src/log/index.js
index 2f9d07ef63c..7e0fb85679b 100644
--- a/packages/dd-trace/src/log/index.js
+++ b/packages/dd-trace/src/log/index.js
@@ -1,6 +1,7 @@
 'use strict'
 
 const coalesce = require('koalas')
+const { inspect } = require('util')
 const { isTrue } = require('../util')
 const { traceChannel, debugChannel, infoChannel, warnChannel, errorChannel } = require('./channels')
 const logWriter = require('./writer')
@@ -63,7 +64,11 @@ const log = {
       Error.captureStackTrace(logRecord, this.trace)
 
       const fn = logRecord.stack.split('\n')[1].replace(/^\s+at ([^\s]+) .+/, '$1')
-      const params = args.map(a => JSON.stringify(a)).join(', ')
+      const params = args.map(a => {
+        return a && a.hasOwnProperty('toString') && typeof a.toString === 'function'
+          ? a.toString()
+          : inspect(a, { depth: 5, breakLength: Infinity, compact: true })
+      }).join(', ')
       const formatted = logRecord.stack.replace('Error: ', `Trace: ${fn}(${params})`)
 
       traceChannel.publish(Log.parse(formatted))
diff --git a/packages/dd-trace/src/opentracing/span.js b/packages/dd-trace/src/opentracing/span.js
index 00fd51da027..23f885bbabd 100644
--- a/packages/dd-trace/src/opentracing/span.js
+++ b/packages/dd-trace/src/opentracing/span.js
@@ -107,7 +107,7 @@ class DatadogSpan {
 
   toString () {
     const spanContext = this.context()
-    const resourceName = spanContext._tags['resource.name']
+    const resourceName = spanContext._tags['resource.name'] || ''
     const resource = resourceName.length > 100
       ? `${resourceName.substring(0, 97)}...`
       : resourceName
diff --git a/packages/dd-trace/src/priority_sampler.js b/packages/dd-trace/src/priority_sampler.js
index 58808fe43a6..3a89f71f664 100644
--- a/packages/dd-trace/src/priority_sampler.js
+++ b/packages/dd-trace/src/priority_sampler.js
@@ -57,7 +57,7 @@ class PrioritySampler {
 
   isSampled (span) {
     const priority = this._getPriorityFromAuto(span)
-    log.trace(span.toString())
+    log.trace(span)
     return priority === USER_KEEP || priority === AUTO_KEEP
   }
 
@@ -71,7 +71,7 @@ class PrioritySampler {
     if (context._sampling.priority !== undefined) return
     if (!root) return // noop span
 
-    log.trace(span.toString(), auto)
+    log.trace(span, auto)
 
     const tag = this._getPriorityFromTags(context._tags, context)
 
@@ -126,7 +126,7 @@ class PrioritySampler {
 
     const root = context._trace.started[0]
 
-    log.trace(span.toString(), samplingPriority, mechanism)
+    log.trace(span, samplingPriority, mechanism)
     this._addDecisionMaker(root)
   }
 
diff --git a/packages/dd-trace/test/log.spec.js b/packages/dd-trace/test/log.spec.js
index a2012be64bb..16682f97db8 100644
--- a/packages/dd-trace/test/log.spec.js
+++ b/packages/dd-trace/test/log.spec.js
@@ -148,10 +148,14 @@ describe('log', () => {
 
       it('should log to console after setting log level to trace', function foo () {
         log.toggle(true, 'trace')
-        log.trace('argument', { hello: 'world' })
+        log.trace('argument', { hello: 'world' }, {
+          toString: () => 'string'
+        }, { foo: 'bar' })
 
         expect(console.debug).to.have.been.calledOnce
-        expect(console.debug.firstCall.args[0]).to.match(/^Trace: Test.foo\("argument", {"hello":"world"}\)/)
+        expect(console.debug.firstCall.args[0]).to.match(
+          /^Trace: Test.foo\('argument', { hello: 'world' }, string, { foo: 'bar' }\)/
+        )
         expect(console.debug.firstCall.args[0].split('\n').length).to.be.gte(3)
       })
     })