OpenAI Codex Tutorial #6 - Using the AGENTS.md file — Transcript

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1. 0:00Okay then my friends in the previous
2. 0:02lesson we talked about commands which
3. 0:04come baked into the Codex CLI tool and
4. 0:07one of those commands was the init
5. 0:08command which generates an agents.md
6. 0:11file for us in this project. Now we're
7. 0:13going to run this command shortly but
8. 0:15just very quickly first of all I want to
9. 0:16talk about what an agents file actually
10. 0:18is and why we would use one. So you can
11. 0:21think of an agents file as a bit like a
12. 0:24readme but instead of being written for
13. 0:25humans it's written for the coding
14. 0:27agents that you're working with. It
15. 0:29lives in your project, usually in the
16. 0:31root folder, and it tells the agent how
17. 0:33your codebase works, what commands it
18. 0:35should use to build and test things,
19. 0:37what coding styles you prefer, how your
20. 0:39project is structured, and so forth.
21. 0:41It's basically like a little cheat sheet
22. 0:43that helps the agent slot into your
23. 0:44workflow and code basically how you
24. 0:47would like them to code. So, Codeex
25. 0:50leans heavily into this agents.md file.
26. 0:53And whenever you ask Codeex to do
27. 0:55something either locally or on Codex
28. 0:57cloud, it's going to look for that file
29. 0:59in your project, if it's there, it's
30. 1:01going to use any information inside that
31. 1:03file as context within your prompts and
32. 1:05any task that you give it. If you've
33. 1:08used any other AI coding agents like
34. 1:11Claude Code or Copilot, you have
35. 1:13probably seen similar kinds of files in
36. 1:15those things. In Clawed Code, we use a
37. 1:17claw.md file for projectwide
38. 1:19instructions. And in copilot, we use a
39. 1:22copilot instructions markdown file for
40. 1:24the same kind of uh stuff. And these all
41. 1:27serve a similar purpose, right? In that
42. 1:29they give each agent memory and concise
43. 1:32project context. Where they differ is
44. 1:35that the agents.mmd file is being pushed
45. 1:38as a standard across different AI coding
46. 1:41tools. So that instead of juggling these
47. 1:43different files for different coding
48. 1:44agents, the idea is that we can have
49. 1:47just a unified agents file which could
50. 1:50then be used across all of them. And
51. 1:52there's already a bunch of different
52. 1:53tools incorporating this agents.mmd
53. 1:55file. So let's head back to the code
54. 1:58then and use the codec cli to scaffold
55. 2:01an agents file for us. Okay then. So I'm
56. 2:04currently in a codec session and I'm
57. 2:06going to use the init command to
58. 2:08generate a new agents.mmd file. And when
59. 2:12we use this command, codeex is
60. 2:14automatically going to scan the codebase
61. 2:16and scaffold the file for us with any
62. 2:18code styles, testing preferences, and
63. 2:21other things it finds. Sometimes it
64. 2:23might add its own personal preferences
65. 2:25as well. So you have to rein those in a
66. 2:27little bit if you see those. And along
67. 2:29the way, we might need to approve
68. 2:30certain commands as well. But then after
69. 2:32a few moments, it's going to make it for
70. 2:33us and place it in the root of our
71. 2:35project. Okay, so it looks like it's
72. 2:38done it. Let's go and have a look over
73. 2:40here at this new file. And you can see
74. 2:42it's written some fairly comprehensive
75. 2:44guidelines. It's a little lean, but you
76. 2:47can always add to this later. So we have
77. 2:49different headings for different things.
78. 2:50So for example, the project structure
79. 2:52and module organization talks about
80. 2:54where different things live. So we have
81. 2:57the app which lives inside this folder
82. 2:59and then we have different route
83. 3:02segments like this. We also have the
84. 3:04layout and the global CSS file. Reusable
85. 3:07UI components live here. Okay. So that
86. 3:09all looks pretty good. Uh we've got some
87. 3:12building testing and development
88. 3:13commands down here which all look quite
89. 3:16accurate. Yep. Then we have some coding
90. 3:19style and naming conventions. It says
91. 3:21use Pascal case like this. Okay. So
92. 3:24basically this is all generic stuff but
93. 3:26all it's doing is looking at our current
94. 3:29uh project as it is at the moment and
95. 3:32inferring the guidelines from there and
96. 3:34it all looks quite accurate at the
97. 3:36moment. It's got some testing guidelines
98. 3:38down here as well and it talks about
99. 3:41this test folder to put the test inside
100. 3:44and then at the bottom we've got some
101. 3:45commit and pull request guidelines as
102. 3:47well. Awesome. So then you should also
103. 3:50probably commit this agents file to your
104. 3:52GitHub repository if you want the Codex
105. 3:54cloud to use it when you're running
106. 3:56remote tasks because again whenever you
107. 3:58ask it to do something on the cloud it's
108. 4:00going to look for this file
109. 4:01automatically and it's going to use it
110. 4:03as context for that task. And for that
111. 4:05reason I'm going to push this change up
112. 4:07to the GitHub repo once I finish
113. 4:08recording this video just to keep
114. 4:10everything up to date and in sync. And
115. 4:12by the way, this file isn't something
116. 4:14you should just create and forget about.
117. 4:16As your project changes and evolves, you
118. 4:18should update your agent file as well
119. 4:20with anything new the coding agent
120. 4:22should know about. For example, if you
121. 4:24start using particular libraries or
122. 4:26frameworks or if you change your project
123. 4:28structure or testing procedures, etc.
124. 4:31Because if you don't keep the file up to
125. 4:33date, then codeex might go off track and
126. 4:35do things the old way as outlined in the
127. 4:37original agents file if you don't change
128. 4:39it. So definitely come back and update
129. 4:42the file as and when you need to.