Generated banner for Skill Writer
Generated logo for Skill Writer

Skill Writer

SentryOfficialPublished by Sentry

  • Skill
  • Meta (authoring, orchestration, planning, memory)
  • Agent tooling
  • Apache-2.0
  • Low risk
  • Has scripts

From the author

Create, synthesize, and iteratively improve agent skills following the Agent Skills specification. Use when asked to "create a skill", "write a skill", "synthesize sources into a skill", "improve a skill from positive/negative examples", "update a skill", or "maintain skill docs and registration". Handles source capture, precision passes, authoring, registration, and validation.
— the description by Sentry

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

Skill Writer provides a standardized, multi-step framework for the full lifecycle of agent skill development. It acts as a router and guide, ensuring that skills are built with high-value coverage, proper architectural layout, and clear maintenance contracts. By following its defined paths—ranging from synthesis and authoring to iteration and validation—users can produce robust, portable, and well-documented skills that adhere to established design principles and precision standards.

What it does

  • Guides the creation and synthesis of new agent skills from raw sources.
  • Facilitates iterative improvements based on positive and negative performance examples.
  • Enforces a structured reference architecture for skill documentation and runtime files.
  • Provides precision passes to ensure changes are necessary, concise, and impactful.
  • Supports the registration and validation of skills to ensure structural integrity.
  • Offers specialized paths for different execution shapes like routers, subagents, and scripts.

When to use it

  • When you need to create a new agent skill from scratch.
  • When updating or improving an existing skill's logic or documentation.
  • When synthesizing disparate sources into a cohesive, functional skill.
  • When you need to refine a skill's behavior based on specific success or failure examples.
  • When maintaining skill documentation and ensuring it meets registration standards.

Advantages

  • Ensures consistency across all developed agent skills.
  • Minimizes wasted runtime tokens by prioritizing high-value input coverage.
  • Provides clear, actionable paths for different levels of skill complexity.
  • Promotes modularity through a well-defined reference architecture.
  • Includes built-in precision checks to prevent unnecessary bloat or rule redundancy.

Usage examples

“Create a skill for managing cloud infrastructure deployments.”
The agent initiates the synthesis path, identifies the required execution shape, and guides you through authoring the SKILL.md and SPEC.md files.
“Improve this skill based on these failed test cases.”
The agent enters the iteration path, analyzes the provided evidence, and proposes specific updates to the skill's logic or documentation to resolve the failures.

Install

  1. Download the skill as a ZIP:

    https://mp-staging.autogineer.com/agent-skills/getsentry/skill-writer/download
  2. Unzip it into the cross-client skills folder of your project:

    mkdir -p .agents/skills && unzip skill-writer.zip -d .agents/skills

Documentation by Sentry

Skill Writer

Use this as the single canonical workflow for skill creation and improvement. Primary success condition: maximize high-value input coverage before authoring while minimizing wasted runtime tokens.

Follow the workflow steps in order. Load only the reference files required for the step you are on. SKILL.md is the primary router: every bundled reference file should be flat under references/ and listed here with a direct "open when..." reason.

Core Workflow References

Open when you need to...Read
choose the minimum workflow path for create, update, iterate, or research-first workreferences/mode-selection.md
choose the simplest adequate execution shape before deciding filesreferences/execution-shapes.md
apply writing constraints for depth, concision, and portabilityreferences/design-principles.md
decide what belongs in SKILL.md, references/, SPEC.md, or supporting filesreferences/reference-architecture.md
create or update the maintenance contract for a skillreferences/spec-template.md
find missing high-signal sources, including history and regressionsreferences/source-discovery.md
adapt an upstream prompt, workflow, rubric, benchmark, or docs into a skillreferences/source-adaptation.md
run the full synthesis pass with coverage checks and source capturereferences/synthesis-path.md
author or update SKILL.md, SPEC.md, and supporting filesreferences/authoring-path.md
improve trigger language and false-positive/false-negative behaviorreferences/description-optimization.md
iterate from positive, negative, or fix examplesreferences/iteration-path.md
store persistent working and holdout examples for future revisionsreferences/iteration-evidence.md
choose a response template, schema, or output contractreferences/output-contracts.md
add or update evals for a skill's generated outputs or runtime behaviorreferences/skill-evals.md
troubleshoot overloaded layouts, hidden refs, or other structure failuresreferences/structure-troubleshooting.md
register the skill and run final validation checksreferences/registration-validation.md

Artifact Layout References

Open when you need to...Read
keep the whole skill inline in one coherent SKILL.mdreferences/layout-inline-skill.md
split optional deep knowledge into focused routed referencesreferences/layout-reference-backed-skill.md
add scripts for deterministic automation or validationreferences/layout-script-backed-workflow.md
define a skill that is usually invoked with explicit argumentsreferences/layout-argument-driven-skill.md
ship reusable templates, schemas, or other static assetsreferences/layout-asset-template-skill.md

Workflow Mechanic References

Open when you need to...Read
break a task into fixed ordered stepsreferences/workflow-prompt-chaining.md
classify requests and route them to different downstream pathsreferences/workflow-routing.md
split independent work into parallel units or votesreferences/workflow-parallel.md
discover work units dynamically and coordinate worker outputsreferences/workflow-orchestrator-workers.md
run validate-fix-repeat checks during authoring or executionreferences/workflow-validation-loops.md
validate a plan before executing a risky actionreferences/workflow-plan-validate-execute.md

Claude Code References

Open when you need to...Read
use Claude-specific frontmatter or invocation controlsreferences/claude-frontmatter-invocation.md
use Claude argument fields or substitution variablesreferences/claude-argument-substitutions.md
build a skill that runs in isolated context: forkreferences/claude-subagent-fork.md
build a skill that uses Claude hooks for deterministic enforcementreferences/claude-hook-backed.md
use Claude shell preprocessing for dynamic context injectionreferences/claude-dynamic-context.md

Example Profiles

Open when you need to...Read
see the expected depth for a documentation-heavy skillreferences/example-documentation-skill.md
see the expected depth for a workflow-process skillreferences/example-workflow-process-skill.md
see what a good routed skill looks likereferences/example-router-skill.md
see what a good subagent-fork skill looks likereferences/example-subagent-fork-skill.md
see what a good hook-backed skill looks likereferences/example-hook-backed-skill.md

Step 1: Resolve target, path, and shape

  1. Resolve the intended operation (create, update, synthesize, iterate) and inspect workspace prior art before choosing where files belong.

  2. Choose the target skill root from observed conventions. If the canonical location is still unclear after inspection, ask one direct question before editing files.

  3. Read references/mode-selection.md to choose the minimum required workflow paths.

  4. Read references/execution-shapes.md to choose the primary execution shape.

  5. Default to the simplest adequate shape. If selecting a more complex shape, record why simpler shapes were rejected.

  6. Load only the exact artifact-layout, workflow-mechanic, and provider-specific leaf files required by that shape.

  7. Before adding guidance, identify what existing rule, section, or file should be narrowed, replaced, or removed.

  8. Record portability implications before using provider-specific mechanics.

Step 2: Run synthesis when needed

Read references/synthesis-path.md.

  1. Use this path for new skills, material changes, and research-first planning.

  2. Collect and score relevant sources with provenance.

  3. Read references/source-discovery.md when source material is thin, stale, or ambiguous.

  4. Read references/source-adaptation.md when adapting an upstream prompt, workflow, rubric, benchmark, or docs.

  5. Produce source-backed decisions and coverage/gap status, including the class and execution-shape choice.

  6. Load example profiles only when they add concrete depth for the selected class or shape.

  7. If the skill uses provider-specific mechanics, include current official provider docs and capture usage constraints.

  8. Do not move to authoring until required coverage is understood or gaps are explicit.

Step 3: Run iteration first when improving from outcomes/examples

Read references/iteration-path.md first when selected path includes iteration (for example operation iterate).

  1. Capture and anonymize examples with provenance.

  2. Read references/iteration-evidence.md when examples should persist beyond the current turn.

  3. Review skill behavior against working and holdout slices.

  4. Propose improvements from positive/negative/fix evidence.

  5. Carry concrete behavior deltas into authoring.

Skip this step when selected path does not include iteration.

Step 4: Author or update skill artifacts

Read references/authoring-path.md.

  1. Write or update SKILL.md in imperative voice with trigger-rich description.

  2. Keep SKILL.md as the runtime router, not an encyclopedia.

  3. Run the pre-edit precision check in references/authoring-path.md before creating new sections or files.

  4. Read references/reference-architecture.md before adding bulk instructions or new reference files.

  5. Create or update SPEC.md using references/spec-template.md when creating a new skill or materially changing its contract.

  6. Create focused reference files, scripts, and assets only when each one has a clear "open when..." reason and cannot be handled by tightening an existing file.

  7. If you add a bundled reference file, add a direct routing entry for it in this SKILL.md.

  8. Prefer checklists, tables, templates, and input/output examples over explanatory prose.

  9. Follow only the specific artifact-layout, workflow-mechanic, Claude-specific, and output-contract references selected for this skill.

  10. For advanced execution shapes, add the required routing, delegation, or safety contracts before considering the skill complete.

  11. For authoring/generator skills, include transformed examples in references:

  • happy-path

  • secure/robust variant

  • anti-pattern + corrected version

  1. Read references/skill-evals.md when the request asks for evals, regression cases, benchmark cases, or model-graded quality checks for the skill being authored.

  2. After any skill artifact changes, run the post-change precision pass in references/authoring-path.md before description optimization or validation.

Step 5: Optimize description quality

Read references/description-optimization.md.

  1. Validate should-trigger and should-not-trigger query sets.

  2. Reduce false positives and false negatives with targeted description edits.

  3. Keep trigger language generic across providers unless the skill is intentionally provider-specific.

Step 6: Register and validate

Read references/registration-validation.md.

  1. Apply repository registration steps for the active layout you verified in the workspace.

  2. Run quick validation for structural checks.

  3. Review validator warnings, precision-pass results, and coverage gaps with judgment before completion.

Output format

Return:

  1. Summary

  2. Changes Made

  3. Validation Results

  4. Open Gaps

Files

LICENSE

                                 Apache License
                           Version 2.0, January 2004
                        http://www.apache.org/licenses/

   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION

   1. Definitions.

      "License" shall mean the terms and conditions for use, reproduction,
      and distribution as defined by Sections 1 through 9 of this document.

      "Licensor" shall mean the copyright owner or entity authorized by
      the copyright owner that is granting the License.

      "Legal Entity" shall mean the union of the acting entity and all
      other entities that control, are controlled by, or are under common
      control with that entity. For the purposes of this definition,
      "control" means (i) the power, direct or indirect, to cause the
      direction or management of such entity, whether by contract or
      otherwise, or (ii) ownership of fifty percent (50%) or more of the
      outstanding shares, or (iii) beneficial ownership of such entity.

      "You" (or "Your") shall mean an individual or Legal Entity
      exercising permissions granted by this License.

      "Source" form shall mean the preferred form for making modifications,
      including but not limited to software source code, documentation
      source, and configuration files.

      "Object" form shall mean any form resulting from mechanical
      transformation or translation of a Source form, including but
      not limited to compiled object code, generated documentation,
      and conversions to other media types.

      "Work" shall mean the work of authorship, whether in Source or
      Object form, made available under the License, as indicated by a
      copyright notice that is included in or attached to the work
      (an example is provided in the Appendix below).

      "Derivative Works" shall mean any work, whether in Source or Object
      form, that is based on (or derived from) the Work and for which the
      editorial revisions, annotations, elaborations, or other modifications
      represent, as a whole, an original work of authorship. For the purposes
      of this License, Derivative Works shall not include works that remain
      separable from, or merely link (or bind by name) to the interfaces of,
      the Work and Derivative Works thereof.

      "Contribution" shall mean any work of authorship, including
      the original version of the Work and any modifications or additions
      to that Work or Derivative Works thereof, that is intentionally
      submitted to the Licensor for inclusion in the Work by the copyright owner
      or by an individual or Legal Entity authorized to submit on behalf of
      the copyright owner. For the purposes of this definition, "submitted"
      means any form of electronic, verbal, or written communication sent
      to the Licensor or its representatives, including but not limited to
      communication on electronic mailing lists, source code control systems,
      and issue tracking systems that are managed by, or on behalf of, the
      Licensor for the purpose of discussing and improving the Work, but
      excluding communication that is conspicuously marked or otherwise
      designated in writing by the copyright owner as "Not a Contribution."

      "Contributor" shall mean Licensor and any individual or Legal Entity
      on behalf of whom a Contribution has been received by Licensor and
      subsequently incorporated within the Work.

   2. Grant of Copyright License. Subject to the terms and conditions of
      this License, each Contributor hereby grants to You a perpetual,
      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
      copyright license to reproduce, prepare Derivative Works of,
      publicly display, publicly perform, sublicense, and distribute the
      Work and such Derivative Works in Source or Object form.

   3. Grant of Patent License. Subject to the terms and conditions of
      this License, each Contributor hereby grants to You a perpetual,
      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
      (except as stated in this section) patent license to make, have made,
      use, offer to sell, sell, import, and otherwise transfer the Work,
      where such license applies only to those patent claims licensable
      by such Contributor that are necessarily infringed by their
      Contribution(s) alone or by combination of their Contribution(s)
      with the Work to which such Contribution(s) was submitted. If You
      institute patent litigation against any entity (including a
      cross-claim or counterclaim in a lawsuit) alleging that the Work
      or a Contribution incorporated within the Work constitutes direct
      or contributory patent infringement, then any patent licenses
      granted to You under this License for that Work shall terminate
      as of the date such litigation is filed.

   4. Redistribution. You may reproduce and distribute copies of the
      Work or Derivative Works thereof in any medium, with or without
      modifications, and in Source or Object form, provided that You
      meet the following conditions:

      (a) You must give any other recipients of the Work or
          Derivative Works a copy of this License; and

      (b) You must cause any modified files to carry prominent notices
          stating that You changed the files; and

      (c) You must retain, in the Source form of any Derivative Works
          that You distribute, all copyright, patent, trademark, and
          attribution notices from the Source form of the Work,
          excluding those notices that do not pertain to any part of
          the Derivative Works; and

      (d) If the Work includes a "NOTICE" text file as part of its
          distribution, then any Derivative Works that You distribute must
          include a readable copy of the attribution notices contained
          within such NOTICE file, excluding those notices that do not
          pertain to any part of the Derivative Works, in at least one
          of the following places: within a NOTICE text file distributed
          as part of the Derivative Works; within the Source form or
          documentation, if provided along with the Derivative Works; or,
          within a display generated by the Derivative Works, if and
          wherever such third-party notices normally appear. The contents
          of the NOTICE file are for informational purposes only and
          do not modify the License. You may add Your own attribution
          notices within Derivative Works that You distribute, alongside
          or as an addendum to the NOTICE text from the Work, provided
          that such additional attribution notices cannot be construed
          as modifying the License.

      You may add Your own copyright statement to Your modifications and
      may provide additional or different license terms and conditions
      for use, reproduction, or distribution of Your modifications, or
      for any such Derivative Works as a whole, provided Your use,
      reproduction, and distribution of the Work otherwise complies with
      the conditions stated in this License.

   5. Submission of Contributions. Unless You explicitly state otherwise,
      any Contribution intentionally submitted for inclusion in the Work
      by You to the Licensor shall be under the terms and conditions of
      this License, without any additional terms or conditions.
      Notwithstanding the above, nothing herein shall supersede or modify
      the terms of any separate license agreement you may have executed
      with Licensor regarding such Contributions.

   6. Trademarks. This License does not grant permission to use the trade
      names, trademarks, service marks, or product names of the Licensor,
      except as required for reasonable and customary use in describing the
      origin of the Work and reproducing the content of the NOTICE file.

   7. Disclaimer of Warranty. Unless required by applicable law or
      agreed to in writing, Licensor provides the Work (and each
      Contributor provides its Contributions) on an "AS IS" BASIS,
      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
      implied, including, without limitation, any warranties or conditions
      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
      PARTICULAR PURPOSE. You are solely responsible for determining the
      appropriateness of using or redistributing the Work and assume any
      risks associated with Your exercise of permissions under this License.

   8. Limitation of Liability. In no event and under no legal theory,
      whether in tort (including negligence), contract, or otherwise,
      unless required by applicable law (such as deliberate and grossly
      negligent acts) or agreed to in writing, shall any Contributor be
      liable to You for damages, including any direct, indirect, special,
      incidental, or consequential damages of any character arising as a
      result of this License or out of the use or inability to use the
      Work (including but not limited to damages for loss of goodwill,
      work stoppage, computer failure or malfunction, or any and all
      other commercial damages or losses), even if such Contributor
      has been advised of the possibility of such damages.

   9. Accepting Warranty or Additional Liability. While redistributing
      the Work or Derivative Works thereof, You may choose to offer,
      and charge a fee for, acceptance of support, warranty, indemnity,
      or other liability obligations and/or rights consistent with this
      License. However, in accepting such obligations, You may act only
      on Your own behalf and on Your sole responsibility, not on behalf
      of any other Contributor, and only if You agree to indemnify,
      defend, and hold each Contributor harmless for any liability
      incurred by, or claims asserted against, such Contributor by reason
      of your accepting any such warranty or additional liability.

   END OF TERMS AND CONDITIONS

   Copyright 2025 Functional Software, Inc. dba Sentry

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Needs Python

Security

What our scanner noticed· Low risk

  • Scripts that your agent may run

This skill includes scripts that your agent may run. Read them before you use it.

A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.

Attribution and licence

Published by
Sentry
Publisher
Sentry (Official)
Source
getsentry/skills · skills/skill-writer · commit e94f222
Licence
Apache License 2.0 (redistribution allowed)
  • LICENSE (added by AutoGineer from LICENSE)
  • ATTRIBUTION.md (written by AutoGineer)
Synced

AutoGineer is not affiliated with or endorsed by Sentry.

Download ZIP

The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download skill-writer.zip