Reorganize the documentation

[xlamorlette-datadog]

Description

This reorganizes the documentation as follows:

• Rename the doc folder to docs.
• Rename maintainers documentation to design.
• Create a basic development documentation from the 'Test' section of the main readme and the 'Code Style' section of contributing.
• Move the 'Logical Component Relationships' section from doc/readme to design.
• Reference security in the main readme.

Motivation

Get a better organization of the documentation, before updating to bring it up to date.

Additional Notes

Jira ticket: IDMPL-549 C++ Tracer: update and improve architecture documentation

[pr-commenter]

Benchmarks

Benchmark execution time: 2026-07-03 13:17:56

Comparing candidate commit fff3c49 in PR branch xlamorlette/reorganize-documentation with baseline commit 64f90a7 in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 8 metrics, 0 unstable metrics.

Explanation

This is an A/B test comparing a candidate commit's performance against that of a baseline commit. Performance changes are noted in the tables below as:

• 🟩 = significantly better candidate vs. baseline
• 🟥 = significantly worse candidate vs. baseline

We compute a confidence interval (CI) over the relative difference of means between metrics from the candidate and baseline commits, considering the baseline as the reference.

If the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD), the change is considered significant.

Feel free to reach out to #apm-benchmarking-platform on Slack if you have any questions.

More details about the CI and significant changes

You can imagine this CI as a range of values that is likely to contain the true difference of means between the candidate and baseline commits.

CIs of the difference of means are often centered around 0%, because often changes are not that big:

---------------------------------(------|---^--------)-------------------------------->
                              -0.6%    0%  0.3%     +1.2%
                                 |          |        |
         lower bound of the CI --'          |        |
sample mean (center of the CI) -------------'        |
         upper bound of the CI ----------------------'

As described above, a change is considered significant if the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD).

For instance, for an execution time metric, this confidence interval indicates a significantly worse performance:

----------------------------------------|---------|---(---------^---------)---------->
                                       0%        1%  1.3%      2.2%      3.1%
                                                  |   |         |         |
       significant impact threshold --------------'   |         |         |
                      lower bound of CI --------------'         |         |
       sample mean (center of the CI) --------------------------'         |
                      upper bound of CI ----------------------------------'

[datadog-datadog-prod-us1]

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 91.66% (+0.00%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: fff3c49 | Docs | Datadog PR Page | Give us feedback!}

[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: 94c3760cdd

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[dubloom]

In theory, we should call dd-trace-* a client library and not a tracing library acutally.

[xlamorlette-datadog]

Should we call it 'APM client library'?

[xlamorlette-datadog]

I propose 'Datadog C++ Tracer' = 'Datadog APM C++ client library'.

In the main Readme, to be reflected in all documentation files:

# Datadog C++ Tracer

This dd-trace-cpp repository contains the Datadog C++ Tracer, which is the [Datadog Application
Performance Monitoring (APM)](https://docs.datadoghq.com/tracing) C++ client library.

[dubloom]

I do think this kind of information should be in the contributing.md because this is common to people.
Putting this information here is not too much of a deal but it's not super straightforward

[xlamorlette-datadog]

I prefer to have all the documentation for developers (design and development process) side by side in the same folder.

The Contributing document at the root of the repository becomes kind of a link to this documentation:
“Please refer to the documentation to learn about the architecture of the Datadog of C++ Tracing
Library and the development processes, notably testing and code formatting, which are mandatory before submitting code changes.”

I think we could even remove this Contributing document at the root and only keep a tiny Contributing section in the Readme at the root, but I suppose it's better to keep both: a tiny document at the root and a tiny section in the Readme, both redirecting to the documentation in the docs folder (same for Security).

What do you think?

[dubloom]

Personally, I'm not a fan of being redirect across documents in a repo but you're the maintainer and I don't have strong opinions