Sometimes the best ideas come to you while you’re out with friends, floating in the pool, or setting up that beach picnic—lightning hits, and you realize you have the perfect solve for that pesky bug that’s been keeping you up at night. We’ve been there too.

That’s what inspired us to create the new ESC collection. It’s not a manifesto to put down tools and chill at the beach (though that sounds nice too), it’s the recognition that occasionally we have to escape the confines of a desk for the problem-solving to begin.

Clothes. But make it developer.

Long-time fan of the shop already know our hat and socks. “But where’s the tee?” you all cried. You asked. Here it is. Plus, the hat gets a fresh colorway. Plus, you can now walk around the pool and maintain that developer wink with our new pool slides.

Get beach ready

Like to go loud? We have exactly the right outfit for you: our Cabana set of matching shirt and shorts with Mona, Copilot, and Rubber Ducky in full tropical mode. If you prefer something more understated, keep it simple with the linen shirt . Either way, swing our cooler tote over your shoulder, and you’re set.

The hoodie that keeps cool

The black invertocat hoodie is one of our bestsellers. Now you can get one… for your can. This coozie won’t keep you warm, but it will keep your refreshing beverage of choice cool, in more ways than one.

And speaking of drinks—the Mona float is here to keep you hydrated while you lounge in the pool. A floating drink holder shaped like our favorite Octocat. What more do you need?

Still developers. Just shopping

This is a collection for developers, by developers. So, of course, we had to have a little fun with the shopping experience too. We used a lidar scanner to create the background on the images. Head to the GitHub shop to play around with the backgrounds—change the colors, the zoom, and everything in between to fully personalize your shopping experience.

Consider this your --yolo flag for the summer. The ESC collection is live at the GitHub Shop. Browse, add to cart, and take some time for yourself. Just you and a cold drink in a tiny hoodie.

Pssst… we’ve got something cool cooking for the World Cup too, check back soon.

The post Still a developer. Just outside. Our latest GitHub Shop collection is here. appeared first on The GitHub Blog.

We're building three interfaces for Azure SRE Agent: an interactive CLI for humans at a terminal, an agent mode for coding agents that spawn it as a subprocess, and an MCP server for humans inside coding agents and for remote agents in other ecosystems.

The CLI and agent mode are coming. The MCP server ships first. That ordering wasn't obvious at first, and this post is about why we landed there.

Three interfaces, one question: who's actually calling this?

When we started designing the Azure SRE Agent CLI, the question we kept running into was deceptively simple: who's the caller?

A human at 2 AM during an incident? Yes. But also a coding agent mid-session that wants SRE Agent capabilities without leaving VS Code. And a PagerDuty SRE agent running an automated triage loop with no human in the picture. And another Azure SRE Agent instance that wants to delegate a sub-task.

Four callers. Same backend. None of them want the same thing.

The three interfaces map to these callers:

1. Interactive CLI: humans at a terminal, terse and incident-optimized
2. Agent Mode: coding agents like Copilot CLI that spawn it as a subprocess
3. MCP Server: humans inside coding agents, and remote agents in other ecosystems

The MCP server is the one shipping now. Here's why.

The CLI requires someone to reach for it

The interactive CLI and agent mode have something in common: the caller has to know Azure SRE Agent exists and decide to invoke it. A human types a command. A coding agent spawns a subprocess. Either way, it's a deliberate call.

The MCP server works differently. It surfaces itself as tools inside whatever environment the caller is already in. The model decides when to use them. An SRE working in Copilot CLI doesn't open a separate terminal and type a command. They ask a question and the right tool fires. A remote agent in a PagerDuty loop doesn't spawn a subprocess. It speaks a protocol and gets a response.

That's the difference. The CLI requires intent. The MCP server meets callers where they already are.

Two callers, one protocol

The MCP surface has two audiences. They speak the same protocol but come from completely different contexts.

Humans inside coding agents. An SRE in VS Code Copilot, Claude Desktop, GitHub Copilot CLI, or Cursor is already in a session: writing a deployment script, reviewing a runbook, debugging a failing service. They don't want a context switch. They want SRE Agent capabilities alongside the work they're already doing. Connect the MCP server once and it's just there.

Remote agents in other ecosystems. An AWS DevOps agent handling a cross-cloud incident might need to check Azure resource health without bouncing the call to a human. A PagerDuty SRE agent might pull an incident summary as part of its triage loop. One Azure SRE Agent instance might delegate work to another. MCP is what makes any of this work without custom integrations on both sides. Both sides agree on the protocol. Neither side has to know the other's internals.

Tool descriptions are product decisions

Each MCP tool maps to a specific SRE Agent capability. Tools have names, descriptions in natural language, and JSON input schemas. The descriptions do more work than they look like they should.

When someone in Copilot CLI asks "what's wrong with my API gateway," the model reads tool descriptions to decide which tool to call. A description that says "Returns health status for an Azure resource" gets invoked less reliably than one that says "Check whether an Azure resource (VM, gateway, database, container) is healthy, degraded, or unreachable. Use this when diagnosing an active outage or validating state after a deployment."

The second version tells the model when to reach for the tool, not just what it does. PM, engineering, and content design reviewed descriptions together. When an invocation misfired in testing, the fix was almost always the description, not the schema.

We iterated on tool descriptions the same way you'd iterate on a system prompt, because that's what they are.

One output shape, two callers

The human-in-a-coding-agent and the remote-agent-in-an-automated-loop want different things from the same tool response. A human wants something readable. A remote agent wants something parseable. The obvious answer is to return different shapes based on who's calling.

We didn't do that.

Every tool response follows the same contract: defined fields, stable semantics, no preamble, no internal reasoning, plus one summary field with a plain-language sentence. A human reads the summary. A remote agent ignores it and parses the structured fields. The overhead is negligible in both directions.

We briefly considered branching on a caller-type hint in the request header. The problem: it added surface area to maintain and created subtle failure modes when the hint was wrong or missing. One shape, always.

What's harder than it looks

Statelessness is a feature for remote agents and friction for humans. MCP tools are stateless by design. Each invocation is independent. Remote agents love this; they don't want to manage session state across calls. Humans working interactively want context to carry forward. We handled it by making every response self-sufficient: the tool returns enough context that the model can construct a coherent follow-up call without re-explaining the situation. The tool doesn't remember. It returns enough that memory is cheap for whoever holds it.

You can't test the remote agent use case the same way you test the human use case. Spin up Copilot CLI, connect the server, ask a question and you can watch what happens. You can't easily simulate an AWS agent calling you cold with no prior context about what Azure SRE Agent does. Designing for that caller meant writing descriptions and schemas that work for a model meeting your tools for the first time, with no assumed vocabulary and no assumed workflow.

What's next

The interactive CLI and agent mode follow the same three-node architecture. The interactive CLI is for humans at the terminal: terse, incident-optimized, with progressive disclosure. Agent Mode is for coding agents that spawn the CLI as a subprocess and want direct access to SRE Agent capabilities without a protocol layer in between. Both are in progress.

In the meantime connect SRE Agent to your MCP client and it will show up where you're already working.

Part of a series on the design decisions behind Azure SRE Agent. Companion posts on the CLI and agent mode will follow when they ship.

Today we’re expanding model choice in Microsoft 365 Copilot with the addition of Anthropic’s latest model—Claude Opus 4.8. Available now in Copilot Cowork (Frontier) and rolling out to Copilot Chat, Excel, PowerPoint, and Copilot Studio. 

Opus 4.8 builds on Opus 4.7 and previous Opus model strengths. It is designed for complex, multi-step coding tasks and long-horizon agentic work—with improved tool selection, closer adherence to your instructions, and better follow-through across multi-turn workflows.

Opus 4.8 is also stronger at drafting documents, data analysis, and presentations and when combined with Work IQ your outputs are grounded in your organization's context, so they're more relevant to your work.

We’re committed to bringing you the latest AI innovation and model choice for work, supported by Microsoft’s enterprise-grade security, compliance, and privacy commitments.

Get started today 

Claude Opus 4.8 is available today in the model selector for eligible users in Copilot Cowork (Frontier) and rolling out to Microsoft 365 Copilot licensed users in Copilot Chat, Excel, PowerPoint, and Copilot Studio early release cycle environments. 

Our team will continue to refine the experience based on your feedback. 

For more details on the model, see Anthropic’s announcement of Claude Opus 4.8 here

As AI applications become more complex, teams need models that can handle longer-running work, reason more deeply across complex analysis use tools more reliably across multi-step workflows, and support consistency for production workflows. Claude Opus 4.8 is designed for these demands, with stronger performance across software development, agents, document-heavy analysis, and enterprise workflows.

Built for complex coding work

Claude Opus 4.8 is designed to support real-world software development tasks, from feature work and debugging to refactoring, migrations, and multi-stage coding projects.

The model can read and reason across codebases, plan before making edits, track dependencies across longer sessions, and continue working through complex tasks with less manual intervention. This makes it well suited for developer workflows where the model needs to understand context, make changes carefully, and maintain coherence over longer periods of work.

Stronger support for agentic workflows

Claude Opus 4.8 also brings improvements for agentic tasks. It is designed to use tools more reliably across multi-step workflows, recover from errors, and problem solve more creatively.

For teams building customer-facing agents, internal automation, or complex workflow orchestration, this matters because agents need more than one-step accuracy. They need to plan, take action, adapt when something fails, and stay within the scope of the task.

Deeper reasoning for enterprise work

In addition to coding and agents, Claude Opus 4.8 is designed for professional work that requires reasoning across long documents, complex inputs, and multiple sources.

This can support use cases such as research synthesis, financial analysis, contract review, regulatory workflows, cybersecurity analysis, and other document-heavy enterprise tasks where consistency and depth are important.

Example use cases

Claude Opus 4.8 can support a range of horizontal and industry-specific scenarios, including:

Software development: Feature work, debugging, code review, refactoring, and large-scale migrations sustained across long sessions in real codebases.

Research and analysis: Synthesizing long documents, producing structured briefs, and generating analysis across multiple sources on the first pass.

Agents and automation: Multi-step workflows that require tool use, planning, and error recovery withlimited oversight.

Financial services: Investment research, earnings analysis, and compliance workflows.

Legal: Contract review, redlining, due diligence, legal research, and draft preparation.

Life sciences: Literature review, clinical documentation, regulatory submission drafting, and trial data synthesis.

Cybersecurity: Threat intelligence synthesis, vulnerability analysis, alert triage, incident response, and security code review.

Available in Microsoft Foundry

With Claude Opus 4.8 available in Microsoft Foundry, developers can access the model as part of a broader platform for building, evaluating, deploying, and operating AI applications.

Microsoft Foundry gives teams a unified environment to work with leading models, compare model fit for their scenarios, evaluate performance against their own data, and move from experimentation to production with enterprise controls.

Claude Opus 4.8 expands the Claude model choice available in Microsoft Foundry and gives teams another strong option for building advanced AI applications that require coding strength, agentic capability, and deep reasoning for enterprise workflows.

Try it today AI Model Catalog | Microsoft Foundry Models

Join us next week at Build to learn more about how to use Claude models in Foundry.

The Rust team is happy to announce a new version of Rust, 1.96.0. Rust is a programming language empowering everyone to build reliable and efficient software.

If you have a previous version of Rust installed via rustup, you can get 1.96.0 with:

$ rustup update stable

If you don't have it already, you can get rustup from the appropriate page on our website, and check out the detailed release notes for 1.96.0.

If you'd like to help us out by testing future releases, you might consider updating locally to use the beta channel (rustup default beta) or the nightly channel (rustup default nightly). Please report any bugs you might come across!

What's in 1.96.0 stable

New Range* types

Many users expect Range and related core::ops types to be Copy, but this is not the case: they implement Iterator directly, and it is a footgun to implement both Iterator and Copy on the same type so this has been avoided. RFC3550 proposed a set of replacement range types that implement IntoIterator rather than Iterator, meaning they can also be Copy. The standard library portion of that RFC is now stable, introducing:

• core::range::Range
• core::range::RangeFrom
• core::range::RangeInclusive
• Associated iterators

A Rust version in the near future will also add core::range::RangeFull and core::range::RangeTo as re-exports from core::ops (these do not implement Iterator and already implement Copy), and core::range::legacy::* as the new home for the current ranges. Range syntax like 0..1 still produces the legacy types for now, but will be updated to core::range types in a future edition.

With these stabilizations, it is now possible to store slice accessors in Copy types without splitting start and end:

use core::range::Range;

#[derive(Clone, Copy)]
pub struct Span(Range<usize>);

impl Span {
    pub fn of(self, s: &str) -> &str {
        &s[self.0]
    }
}

The new RangeInclusive also makes its fields public, unlike the legacy version which avoided exposing the exhausted iterator state. This isn't a concern with the new type since it must be converted to begin iteration.

Library authors should consider making use of impl RangeBounds in public API, which accepts both legacy and new range types. If a concrete type is needed, prefer using new ranges as this will eventually become the default.

Assert matching patterns

The new macros assert_matches! and debug_assert_matches! check that a value matches a given pattern, panicking with a Debug representation of the value otherwise. These are essentially the same as assert!(matches!(..)) and debug_assert!(matches!(..)), but the printed value improves the possibility of diagnosing the failure.

These new macros have not been added to the standard prelude, because they would collide with popular third-party crates that provide macros with the same name. Instead, they should be manually imported from core or std before use.

use core::assert_matches;

/// [Random Number](https://xkcd.com/221/)
fn get_random_number() -> u32 {
    // chosen by a fair dice roll.
    // guaranteed to be random.
    4
}

fn main() {
    assert_matches!(get_random_number(), 1..=6);
}

Changes to WebAssembly targets

WebAssembly targets no longer pass --allow-undefined to the linker which means that undefined symbols when linking are now a linker error instead of being converted to WebAssembly imports from the "env" module. This change prevents modules from linking unless all linking-related symbols are defined to catch bugs earlier and prevent accidental issues with symbol naming or similar.

Undefined linking-related symbols are often indicative of build-time related bugs or misconfiguration. If, however, the old behavior is intended then it can be re-enabled with RUSTFLAGS=-Clink-arg=--allow-undefined or by editing the source code and using #[link(wasm_import_module = "env")] on the block defining the symbol.

This change was previously announced on this blog, and now takes effect in Rust 1.96.

Stabilized APIs

• assert_matches!
• debug_assert_matches!
• From<T> for AssertUnwindSafe<T>
• From<T> for LazyCell<T, F>
• From<T> for LazyLock<T, F>
• core::range::RangeToInclusive
• core::range::RangeToInclusiveIter
• core::range::RangeFrom
• core::range::RangeFromIter
• core::range::Range
• core::range::RangeIter

Two Cargo advisories

Rust 1.96 contains fixes for two vulnerabilities for users of third-party registries.

• CVE-2026-5223 is a medium severity vulnerability regarding extraction of crate tarballs with symlinks.

• CVE-2026-5222 is a low severity vulnerability regarding authentication with normalized URLs.

Users of crates.io are not affected by either vulnerability.

Other changes

Check out everything that changed in Rust, Cargo, and Clippy.

Contributors to 1.96.0

Many people came together to create Rust 1.96.0. We couldn't have done it without all of you. Thanks!

There’s and important Wolverine 6.1.0 enhancement release this week that follows up on the big Critter Stack 2026 wave with even more improvements to our “cold start” performance. Specifically today, I’d actually like to talk about how we improved and extended the command line diagnostics tools in the Critter Stack to make it faster and more useful — especially in our new world order of AI assisted software development.

If you’ll pay attention to a coding agent at work, you’ll notice that it’s doing a lot of brute force work through successive command line calls on your system. It turns out that exposing diagnostic information about your system or database or really any system state through command line tools that generate easily parseable information to stdout turns out to be a great way to enable AI agents. You could even say (with a cringe) that:

Now though, the AI utilization of command line tools brings us to some new needs:

• It would be awfully nice to optimize the command line tools for faster cycles now that it’s a machine trying to utilize the output rather than a human who probably won’t hardly notice some minor delays due to command discovery and application bootstrapping
• The command line output in some cases now needs to be optimized for terse, easily parsed data that will be read by the AI agent

Alright, back to the Critter Stack. Buried all the way at the bottom of our stack is a command line parser that originated with FubuMVC about 15 years ago. The value of our particular CLI tooling is that it allows you to utilize custom commands discovered in assemblies within your system. We’ve depended on that pretty heavily over the years to introduce quite a few built in utilities for managing dependencies, environment checks, projection rebuilds, and database management.

This seems to be a good point to give a shoutout to Spectre Console that we use internally to make our output a lot prettier than it would be otherwise.

Here’s a little visualization of the various commands hanging out across the Critter Stack:

And of course, many folks will utilize our command line discovery to create their own CLI commands for any number of their own custom diagnostics, batch job runners, or data loading tasks that can be baked directly into their application.

All good so far? It’s been a very useful subsystem for us, but the auto-magic wiring of commands from all these assemblies in your system was enabled by assembly scanning to discover concrete command types upfront.

For the recent “Critter Stack 2026” wave of releases, we switched the command discovery to relying on a source generator (JasperFx.SourceGenerator) to build in the discovery and even more of the parsing code up front to reduce the time it takes a JasperFx CLI enabled application to spin up and be ready to work. This was done quite purposely to optimize the cycle time for AI agent usage, especially if you’re running from pre-compiled code. We also made some optimizations to the command parsing itself too.

Step 1: Get the Big Picture with describe

For the exhaustive flag-by-flag reference, see the Command Line Integration and Diagnostics guides.

First off, if you have either Marten, Polecat, or Wolverine active in your codebase, you can add this line at the very bottom of your Program file (or Program.Main() method, same difference) that opts into the JasperFx command line runner:

// Opt into JasperFx for command line parsing to unlock the built in
// diagnostics and utility tools within your Wolverine application
// And this *exact* signature is important so that the exit code is
// correctly handled to denote failures!
return await app.RunJasperFxCommands(args);

You can verify that the JasperFx is enabled by:

dotnet run help

And also, dotnet run help [command name] to see the specific arguments and flag usage of any specific command.

Wolverine and Marten are a configuration-heavy with plenty of options that impact behavior. Conventions, policies, middleware, transports, and explicit routing all layer together, which is powerful — but it can leave you asking “what is my app actually doing?” For that, we have this command that’s writes out a textual report

dotnet run describe

 describe prints a series of tabular reports about the running configuration:

• Wolverine Options — the basics, including which assembly Wolverine thinks is your application assembly and which extensions loaded
• Listeners — every configured listening endpoint and local queue, with how each is configured
• Message Routing — where known, published message types are routed
• Sending Endpoints — configured endpoints that send messages externally
• Error Handling — a preview of the active message-failure policies
• HTTP Endpoints — all Wolverine HTTP endpoints (only when WolverineFx.Http is in use)
• Marten or Polecat configuration

This is also the report that I will most often ask you to paste when you need help online.

Step 2: See the Code Wolverine Generates

Wolverine generates the adapter code around your handlers and HTTP endpoints at startup. When you want to see it — what middleware ran, how dependencies resolve, where transactions wrap — write it out or preview it:

# Write all generated code to /Internal/Generated
dotnet run -- codegen write

# Or just dump it to the terminal
dotnet run -- codegen preview

codegen covers the whole app, which can be noisy. When you want to understand a single entry point, reach for codegen-preview under the wolverine-diagnostics parent command :

# A message handler (fully-qualified, short, or handler class name — fuzzy matched)
dotnet run -- wolverine-diagnostics codegen-preview --handler CreateOrder

# An HTTP endpoint (requires Wolverine.Http; format "METHOD /path")
dotnet run -- wolverine-diagnostics codegen-preview --route "POST /api/orders"

# A proto-first gRPC service (requires Wolverine.Grpc)
dotnet run -- wolverine-diagnostics codegen-preview --grpc Greeter

The output is identical to codegen preview, but scoped to one handler, so the signal-to-noise ratio is far higher. This command was 100% meant for AI tool usage, but it’s hopefully helpful for human usage. We have been investing in JasperFx’s curated AI skills to “know” how to use these tools to troubleshoot Critter Stack application building inside of AI coding agent work.

Conveniently enough, you are now able to purchase access to our curated AI Skills online — but these are also bundled into JasperFx Software support plans.

We’re going to add an interactive mode to the new wolverine-diagnostics tool soon for easier human usage.

Step 3: Understand Where and Why Messages Route

describe shows you the routing table. When you need to focus on one message type — or understand why it routes the way it does — use describe-routing :

# One message type (full name, short name, or fuzzy match)
dotnet run -- wolverine-diagnostics describe-routing CreateOrder

# The complete routing topology
dotnet run -- wolverine-diagnostics describe-routing --all

For a single type you get the local handler, a routes table (destination, local vs. external, Buffered/Durable/Inline mode, outbox enrollment, serializer, and how each route was resolved), and any message-level attributes such as [DeliverWithin].

The most useful flag is --explain , which walks Wolverine’s route-source chain in order and shows what each source produced and which terminating source short-circuited the rest:

dotnet run -- wolverine-diagnostics describe-routing CreateOrder --explain

# Same explanation as structured JSON, for tooling or AI agents
dotnet run -- wolverine-diagnostics describe-routing CreateOrder --json

This is the command-line surface over the IWolverineRuntime.ExplainRoutingFor(Type) API. The text output is deliberately stable and labeled so it reads well for humans and parses cleanly for automated tooling. See Troubleshooting Message Routing for the programmatic side.

Step 4: Troubleshoot Handler Discovery

If you expected Wolverine to find a handler but it isn’t running, ask Wolverine to explain its discovery decision for that type:

# By handler class name (also accepts a fully-qualified name or a fuzzy partial match)
dotnet run -- wolverine-diagnostics describe-handlers CreateOrderHandler

The argument is matched against the types in your application, and if it matches more than one type you get a report for each. Every report tells you whether the type’s assembly is being scanned, which type-level include/exclude rules HIT or MISS, and — per method — whether it satisfies the handler naming and signature conventions. It’s the command-line surface over WolverineOptions.DescribeHandlerMatch(Type), so you don’t have to drop a temporary Console.WriteLine(...) into your bootstrapping code (see Troubleshooting Handler Discovery).

Step 5: Check Your Infrastructure

Wolverine’s transports and the durable inbox/outbox register self-diagnosing environment checks — can I reach the database? the broker? are the IoC registrations valid?

dotnet run -- check-env

To create, inspect, or tear down the stateful infrastructure Wolverine needs (queues, tables, topics):

dotnet run -- resources setup     # also: check, list, teardown, statistics

resources setup is a great way to provision a clean environment before a test run.

Step 6: Inspect and Recover Message Storage

For applications using the durable inbox/outbox, the storage command administers the message store:

dotnet run -- storage counts     # incoming / outgoing / scheduled / dead-letter / handled
dotnet run -- storage clear
dotnet run -- storage rebuild                                   # --file to emit the schema script
dotnet run -- storage release --exception-type Some.Exception   # replay dead-lettered messages

storage counts is the quick “is anything backing up?” check, and release re-queues dead-lettered envelopes (optionally filtered to a single exception type). To purge inbox rows already marked Handled:

dotnet run -- clear-handled

Step 7: Export a Full Snapshot with capabilities

dotnet run -- capabilities wolverine.json

Writes a complete JSON description of the application — settings, message types, message store, messaging endpoints, even configured event stores. It’s useful for support, for feeding external tooling, and for detecting unintended configuration drift between deployments.

Bonus: Generate OpenAPI Offline (Wolverine.Http)

If you use WolverineFx.Http, you can generate the OpenAPI document without starting the host — no database or broker required, which makes it CI-friendly:

dotnet run -- openapi --list                  # list document names from AddOpenApi()
dotnet run -- openapi -d v1 -o swagger.json    # generate a document to a file
dotnet run -- openapi --route "GET /orders/{id}"

Cheat Sheet

Where to Go Next

• Command Line Integration — the full reference, including every flag
• Diagnostics — handler-discovery troubleshooting and the routing-explanation API
• Code Generation — how Wolverine’s generated code works

Wait, how does this work with Aspire?

But wait, what if you’re using Aspire as a de facto replacement for docker compose locally such that your applications can’t really run without Aspire being started up first? How is that going to work?

Um, I need to have a better answer for that myself. Let me get back to you on that one!

So, what’s JasperFx Software’s game plan for AI?

We’re going to throw all the spaghetti up against the wall!

More seriously, we’re going to bet on the command line usage described here + AI Skills combination as our first step. We’re also building quite a bit of MCP support into the CritterWatch commercial tooling that will hopefully be generally available in the next couple weeks. The last bit of planned spaghetti is some spec driven development experimentation we’re doing off in the background that’s going down a Behavior Driven Development strategy rather than trying for any kind of user interface modelling approach.