feat: Sprint 23 — agentic transparency + polish

Track A: Token/cost display
- Read agent usage attrs (session_prompt_tokens, session_completion_tokens,
  session_estimated_cost_usd) after run_conversation in streaming.py
- Add input_tokens, output_tokens, estimated_cost fields to Session model
- Include usage in done SSE event payload
- Store usage on S.lastUsage in messages.js done handler
- Render usage badge below last assistant message (input/output/cost)

Track B: Subagent delegation cards
- Add subagent_progress to toolIcon map with shuffle emoji
- Special-case subagent_progress in buildToolCard: "Subagent" label,
  strip double emoji from preview, add tool-card-subagent CSS class
- Indented border-left styling for subagent cards
- Clean delegate_task display name

Track C: Skill picker in cron create form
- Add skill search input + tag chips to cron create form HTML
- Skill picker JS in panels.js: search/filter, click-to-add tags,
  remove tag chips, pre-fetch skill list on form open
- submitCronCreate sends skills array in POST body
- Skill picker dropdown + tag CSS

Track D: Skill linked files viewer
- Add file query param to /api/skills/content endpoint
- Serve linked files from skill directory with path traversal protection
- Ensure linked_files key always present in skill content response
- Render linked files section below SKILL.md content in preview panel
- openSkillFile function for viewing individual linked files

Track E: Bug fixes and code quality
- Expand Session.__init__ and compact() to readable multi-line format
- Remove inline import json as _j2 inside loop in streaming.py
- Fix tool_calls: capture args from assistant messages, skip unresolved names
- Store args snapshot in persisted tool_calls for reload display

6 new tests. Total: 421 (409 passing).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

static/index.html

@@ -45,11 +45,16 @@
         <input id="cronFormName" placeholder="Job name (optional)" style="width:100%;background:rgba(255,255,255,.05);border:1px solid var(--border2);border-radius:6px;color:var(--text);padding:5px 8px;font-size:12px;outline:none;margin-bottom:6px">
         <input id="cronFormSchedule" placeholder="Schedule: '0 9 * * *' or 'every 1h'" style="width:100%;background:rgba(255,255,255,.05);border:1px solid var(--border2);border-radius:6px;color:var(--text);padding:5px 8px;font-size:12px;outline:none;margin-bottom:6px">
         <textarea id="cronFormPrompt" rows="3" placeholder="Prompt (must be self-contained)" style="width:100%;background:rgba(255,255,255,.05);border:1px solid var(--border2);border-radius:6px;color:var(--text);padding:5px 8px;font-size:12px;outline:none;resize:none;font-family:inherit;margin-bottom:6px"></textarea>
-        <select id="cronFormDeliver" style="width:100%;background:rgba(255,255,255,.05);border:1px solid var(--border2);border-radius:6px;color:var(--text);padding:5px 8px;font-size:12px;outline:none;margin-bottom:8px">
+        <select id="cronFormDeliver" style="width:100%;background:rgba(255,255,255,.05);border:1px solid var(--border2);border-radius:6px;color:var(--text);padding:5px 8px;font-size:12px;outline:none;margin-bottom:6px">
           <option value="local">Local (save output only)</option>
           <option value="discord">Discord</option>
           <option value="telegram">Telegram</option>
         </select>
+        <div class="skill-picker-wrap" style="margin-bottom:8px">
+          <input id="cronFormSkillSearch" placeholder="Add skills (optional)..." style="width:100%;background:rgba(255,255,255,.05);border:1px solid var(--border2);border-radius:6px;color:var(--text);padding:5px 8px;font-size:12px;outline:none" autocomplete="off">
+          <div id="cronFormSkillDropdown" class="skill-picker-dropdown" style="display:none"></div>
+          <div id="cronFormSkillTags" class="skill-picker-tags"></div>
+        </div>
         <div style="display:flex;gap:6px">
           <button class="cron-btn run" style="flex:1" onclick="submitCronCreate()">Create job</button>
           <button class="cron-btn" style="flex:1" onclick="toggleCronForm()">Cancel</button>

static/messages.js

@@ -146,6 +146,7 @@ async function send(){
       }
       if(S.session&&S.session.session_id===activeSid){
         S.session=d.session;S.messages=d.session.messages||[];
+        if(d.usage) S.lastUsage=d.usage;
         if(d.session.tool_calls&&d.session.tool_calls.length){
           S.toolCalls=d.session.tool_calls.map(tc=>({...tc,done:true}));
         } else {

static/panels.js

@@ -79,6 +79,9 @@ async function loadCrons() {
   } catch(e) { box.innerHTML = `<div style="padding:12px;color:var(--accent);font-size:12px">Error: ${esc(e.message)}</div>`; }
 }
 
+let _cronSelectedSkills=[];
+let _cronSkillsCache=null;
+
 function toggleCronForm(){
   const form=$('cronCreateForm');
   if(!form)return;
@@ -90,10 +93,65 @@ function toggleCronForm(){
     $('cronFormPrompt').value='';
     $('cronFormDeliver').value='local';
     $('cronFormError').style.display='none';
+    _cronSelectedSkills=[];
+    _renderCronSkillTags();
+    const search=$('cronFormSkillSearch');
+    if(search)search.value='';
+    // Pre-fetch skills for the picker
+    if(!_cronSkillsCache){
+      api('/api/skills').then(d=>{_cronSkillsCache=d.skills||[];}).catch(()=>{});
+    }
     $('cronFormName').focus();
   }
 }
 
+function _renderCronSkillTags(){
+  const wrap=$('cronFormSkillTags');
+  if(!wrap)return;
+  wrap.innerHTML='';
+  for(const name of _cronSelectedSkills){
+    const tag=document.createElement('span');
+    tag.className='skill-tag';
+    tag.innerHTML=esc(name)+'<span class="remove-tag" onclick="this.parentElement.remove();_cronSelectedSkills=_cronSelectedSkills.filter(s=>s!==\''+esc(name)+'\')">×</span>';
+    wrap.appendChild(tag);
+  }
+}
+
+// Skill search input handler
+(function(){
+  const setup=()=>{
+    const search=$('cronFormSkillSearch');
+    const dropdown=$('cronFormSkillDropdown');
+    if(!search||!dropdown)return;
+    search.oninput=()=>{
+      const q=search.value.trim().toLowerCase();
+      if(!q||!_cronSkillsCache){dropdown.style.display='none';return;}
+      const matches=_cronSkillsCache.filter(s=>
+        !_cronSelectedSkills.includes(s.name)&&
+        (s.name.toLowerCase().includes(q)||(s.category||'').toLowerCase().includes(q))
+      ).slice(0,8);
+      if(!matches.length){dropdown.style.display='none';return;}
+      dropdown.innerHTML='';
+      for(const s of matches){
+        const opt=document.createElement('div');
+        opt.className='skill-opt';
+        opt.textContent=s.name+(s.category?' ('+s.category+')':'');
+        opt.onclick=()=>{
+          _cronSelectedSkills.push(s.name);
+          _renderCronSkillTags();
+          search.value='';
+          dropdown.style.display='none';
+        };
+        dropdown.appendChild(opt);
+      }
+      dropdown.style.display='';
+    };
+    search.onblur=()=>setTimeout(()=>{dropdown.style.display='none';},150);
+  };
+  if(document.readyState==='loading')document.addEventListener('DOMContentLoaded',setup);
+  else setTimeout(setup,0);
+})();
+
 async function submitCronCreate(){
   const name=$('cronFormName').value.trim();
   const schedule=$('cronFormSchedule').value.trim();
@@ -104,7 +162,10 @@ async function submitCronCreate(){
   if(!schedule){errEl.textContent='Schedule is required (e.g. "0 9 * * *" or "every 1h")';errEl.style.display='';return;}
   if(!prompt){errEl.textContent='Prompt is required';errEl.style.display='';return;}
   try{
-    await api('/api/crons/create',{method:'POST',body:JSON.stringify({name:name||undefined,schedule,prompt,deliver})});
+    const body={schedule,prompt,deliver};
+    if(name)body.name=name;
+    if(_cronSelectedSkills.length)body.skills=_cronSelectedSkills;
+    await api('/api/crons/create',{method:'POST',body:JSON.stringify(body)});
     toggleCronForm();
     showToast('Job created ✓');
     await loadCrons();
@@ -344,12 +405,45 @@ async function openSkill(name, el) {
     $('previewBadge').textContent = 'skill';
     $('previewBadge').className = 'preview-badge md';
     showPreview('md');
-    $('previewMd').innerHTML = renderMd(data.content || '(no content)');
+    let html = renderMd(data.content || '(no content)');
+    // Render linked files section if present
+    const lf = data.linked_files || {};
+    const categories = Object.entries(lf).filter(([,files]) => files && files.length > 0);
+    if (categories.length) {
+      html += '<div class="skill-linked-files"><div style="font-size:11px;font-weight:600;color:var(--muted);text-transform:uppercase;letter-spacing:.05em;margin-bottom:8px">Linked Files</div>';
+      for (const [cat, files] of categories) {
+        html += `<div class="skill-linked-section"><h4>${esc(cat)}</h4>`;
+        for (const f of files) {
+          html += `<a class="skill-linked-file" onclick="openSkillFile('${esc(name)}','${esc(f)}');return false" href="#">${esc(f)}</a>`;
+        }
+        html += '</div>';
+      }
+      html += '</div>';
+    }
+    $('previewMd').innerHTML = html;
     $('previewArea').classList.add('visible');
     $('fileTree').style.display = 'none';
   } catch(e) { setStatus('Could not load skill: ' + e.message); }
 }
 
+async function openSkillFile(skillName, filePath) {
+  try {
+    const data = await api(`/api/skills/content?name=${encodeURIComponent(skillName)}&file=${encodeURIComponent(filePath)}`);
+    $('previewPathText').textContent = skillName + ' / ' + filePath;
+    $('previewBadge').textContent = filePath.split('.').pop() || 'file';
+    $('previewBadge').className = 'preview-badge code';
+    const ext = filePath.split('.').pop() || '';
+    if (['md','markdown'].includes(ext)) {
+      showPreview('md');
+      $('previewMd').innerHTML = renderMd(data.content || '');
+    } else {
+      showPreview('code');
+      $('previewCode').textContent = data.content || '';
+      requestAnimationFrame(() => highlightCode());
+    }
+  } catch(e) { setStatus('Could not load file: ' + e.message); }
+}
+
 // ── Skill create/edit form ──
 let _editingSkillName = null;
 

static/style.css

@@ -562,6 +562,26 @@ body.resizing{user-select:none;cursor:col-resize;}
 /* Show more button inside tool card result */
 .tool-card-more{background:none;border:none;color:var(--blue);font-size:10px;cursor:pointer;padding:3px 0 0;opacity:.7;display:block;}
 .tool-card-more:hover{opacity:1;}
+/* Subagent cards: indented with accent border */
+.tool-card-subagent{border-left:2px solid rgba(124,185,255,.3);margin-left:8px;}
+/* Token usage badge below assistant messages */
+.msg-usage{font-size:11px;color:var(--muted);opacity:.6;margin-top:2px;padding-left:42px;}
+.msg-usage:hover{opacity:1;}
+/* Skill picker (cron create form) */
+.skill-picker-wrap{position:relative;}
+.skill-picker-dropdown{position:absolute;left:0;right:0;top:100%;background:var(--sidebar);border:1px solid var(--border2);border-radius:6px;z-index:10;max-height:180px;overflow-y:auto;box-shadow:0 4px 12px rgba(0,0,0,.3);}
+.skill-opt{padding:6px 10px;cursor:pointer;font-size:12px;color:var(--muted);transition:background .1s;}
+.skill-opt:hover{background:rgba(255,255,255,.08);color:var(--text);}
+.skill-picker-tags{display:flex;flex-wrap:wrap;gap:4px;margin-top:4px;}
+.skill-tag{background:rgba(124,185,255,.12);border:1px solid rgba(124,185,255,.25);border-radius:12px;padding:2px 8px;font-size:11px;color:var(--blue);display:flex;align-items:center;gap:4px;}
+.remove-tag{cursor:pointer;opacity:.6;font-size:13px;line-height:1;}
+.remove-tag:hover{opacity:1;color:var(--accent);}
+/* Skill linked files section */
+.skill-linked-files{margin-top:16px;border-top:1px solid var(--border);padding-top:12px;}
+.skill-linked-section{margin-bottom:8px;}
+.skill-linked-section h4{font-size:10px;text-transform:uppercase;letter-spacing:.05em;color:var(--muted);margin-bottom:4px;}
+.skill-linked-file{display:block;font-size:12px;padding:3px 6px;border-radius:4px;cursor:pointer;color:var(--blue);text-decoration:none;}
+.skill-linked-file:hover{background:rgba(255,255,255,.06);}
 .tool-card-row{margin:0;padding:1px 0;}
 .tool-card{background:rgba(255,255,255,.03);border:1px solid rgba(255,255,255,.07);border-radius:6px;margin:2px 0 2px 40px;overflow:hidden;transition:border-color .15s;}
 .tool-card:hover{border-color:rgba(255,255,255,.12);}

static/ui.js

@@ -82,6 +82,8 @@ let _scrollPinned=true;
     _scrollPinned=nearBottom;
   });
 })();
+function _fmtTokens(n){if(n>=1e6)return(n/1e6).toFixed(1)+'M';if(n>=1e3)return(n/1e3).toFixed(1)+'k';return String(n);}
+
 function scrollIfPinned(){
   if(!_scrollPinned) return;
   const el=$('messages');
@@ -486,6 +488,21 @@ function renderMessages(){
       else inner.appendChild(frag);
     }
   }
+  // Render per-turn usage badge on the last assistant message (if usage data exists)
+  if(S.session&&(S.session.input_tokens||S.session.output_tokens)){
+    const lastAssist=inner.querySelector('.msg-row:last-child');
+    if(lastAssist&&!lastAssist.querySelector('.msg-usage')){
+      const usage=document.createElement('div');
+      usage.className='msg-usage';
+      const inTok=S.session.input_tokens||0;
+      const outTok=S.session.output_tokens||0;
+      const cost=S.session.estimated_cost;
+      let text=`${_fmtTokens(inTok)} in · ${_fmtTokens(outTok)} out`;
+      if(cost) text+=` · ~$${cost<0.01?cost.toFixed(4):cost.toFixed(2)}`;
+      usage.textContent=text;
+      lastAssist.appendChild(usage);
+    }
+  }
   scrollToBottom();
   // Apply syntax highlighting after DOM is built
   requestAnimationFrame(()=>{highlightCode();addCopyButtons();renderMermaidBlocks();});
@@ -499,7 +516,8 @@ function toolIcon(name){
   const icons={terminal:'⬛',read_file:'📄',write_file:'✏️',search_files:'🔍',
     web_search:'🌐',web_extract:'🌐',execute_code:'⚙️',patch:'🔧',
     memory:'🧠',skill_manage:'📚',todo:'✅',cronjob:'⏱️',delegate_task:'🤖',
-    send_message:'💬',browser_navigate:'🌐',vision_analyze:'👁️'};
+    send_message:'💬',browser_navigate:'🌐',vision_analyze:'👁️',
+    subagent_progress:'🔀'};
   return icons[name]||'🔧';
 }
 
@@ -520,13 +538,22 @@ function buildToolCard(tc){
   }
   const hasMore=tc.snippet&&tc.snippet.length>displaySnippet.length;
   const runIndicator=tc.done===false?'<span class="tool-card-running-dot"></span>':'';
+  const isSubagent=tc.name==='subagent_progress';
+  const isDelegation=tc.name==='delegate_task';
+  const cardClass='tool-card'+(tc.done===false?' tool-card-running':'')+(isSubagent?' tool-card-subagent':'');
+  // Clean up subagent preview: strip leading 🔀 emoji since the icon already shows it
+  let displayName=tc.name;
+  if(isSubagent) displayName='Subagent';
+  if(isDelegation) displayName='Delegate task';
+  let previewText=tc.preview||displaySnippet||'';
+  if(isSubagent) previewText=previewText.replace(/^🔀\s*/,'');
   row.innerHTML=`
-    <div class="tool-card${tc.done===false?' tool-card-running':''}">
+    <div class="${cardClass}">
       <div class="tool-card-header" onclick="this.closest('.tool-card').classList.toggle('open')">
         ${runIndicator}
         <span class="tool-card-icon">${icon}</span>
-        <span class="tool-card-name">${esc(tc.name)}</span>
-        <span class="tool-card-preview">${esc(tc.preview||displaySnippet||'')}</span>
+        <span class="tool-card-name">${esc(displayName)}</span>
+        <span class="tool-card-preview">${esc(previewText)}</span>
         ${hasDetail?'<span class="tool-card-toggle">▸</span>':''}
       </div>
       ${hasDetail?`<div class="tool-card-detail">