WASHINGTON — Hours after F.B.I. agents searched the homes of two Project Veritas operatives last week, James O’Keefe, the leader of the conservative group, took to YouTube to defend its work as “the stuff of responsible, ethical journalism.”

“We never break the law,” he said, railing against the F.B.I.’s investigation into members of his group for possible involvement in the reported theft of a diary kept by President Biden’s daughter, Ashley. “In fact, one of our ethical rules is to act as if there are 12 jurors on our shoulders all the time.”

Project Veritas has long occupied a gray area between investigative journalism and political spying, and internal documents obtained by The New York Times reveal the extent to which the group has worked with its lawyers to gauge how far its deceptive reporting practices can go before running afoul of federal laws.

The documents, a series of memos written by the group’s lawyer, detail ways for Project Veritas sting operations — which typically diverge from standard journalistic practice by employing people who mask their real identities or create fake ones to infiltrate target organizations — to avoid breaking federal statutes such as the law against lying to government officials.

The documents show, for example, Project Veritas operatives’ concern that an operation launched in 2018 to secretly record employees at the F.B.I., Justice Department and other agencies in the hope of exposing bias against President Donald J. Trump might violate the Espionage Act — the law passed at the height of World War I that has typically been used to prosecute spies.

“Because intent is relevant — and broadly defined — ensuring PV journalists’ intent is narrow and lawful would be paramount in any operation,” the group’s media lawyer, Benjamin Barr, wrote in response to questions from the group about using the dating app Tinder to have its operatives meet government employees, potentially including some with national security clearances.

In a separate July 2017 memorandum, Mr. Barr emailed a representative of the group that the criminal statute involving false statements to federal officials “continues to be an expansive, dangerous law that inhibits Veritas’s operations.”

The documents give new insight into the workings of the group at a time when it faces potential legal peril in the diary investigation — and has signaled that its defense will rely in part on casting itself as a journalistic organization protected by the First Amendment.

The F.B.I. last week searched the homes of Mr. O’Keefe and two other Project Veritas operatives — Eric Cochran and Spencer Meads — as part of the investigation into the reported theft of Ms. Biden’s diary. Mr. O’Keefe has acknowledged receiving a grand jury subpoena in the case.

Mr. O’Keefe and his lawyer, Paul Calli, revealed new details about the diary investigation and F.B.I. search to Sean Hannity on Fox News on Monday. During the interview, Mr. Calli said that Project Veritas had paid for the right to publish the diary but was unable to confirm it belonged to Ms. Biden and ultimately decided not to go ahead with a story about its contents. Excerpts from the diary were later published by another conservative website.

One of the crimes listed on Mr. O’Keefe’s search warrant was “transporting material across state lines,” his lawyer said. There is a criminal statute against taking stolen goods from one state to another.

Mr. O’Keefe said the F.B.I. took his phones, which had confidential donor and source information. He said that neither he nor his group had done anything wrong, and that the F.B.I. searches were an assault on the First Amendment.

The legal documents obtained by The Times were written several years ago, at a time when Project Veritas was remaking itself from a small operation running on a shoestring budget to a group more closely modeled on a small intelligence-gathering organization.

During the Trump administration, the group saw a flood of new donations from both private donors and conservative foundations, and hired former American and British intelligence and military operatives to train Project Veritas agents in spycraft.

In a statement issued by one of its lawyers, Project Veritas said it “stands behind these legal memos and is proud of the exhaustive work it does to ensure each of its journalism investigations complies with all applicable laws.”

The statement said the work “reflects Project Veritas’s dedication to the First Amendment, which protects the right to gather information, including about those in power.”

Project Veritas is suing The New York Times over a 2020 story about a video the group made alleging voter fraud in Minnesota.

Most news organizations consult regularly with lawyers, but some of Project Veritas’s questions for its legal team demonstrate an interest in using tactics that test the boundaries of legality and are outside of mainstream reporting techniques.

In a February 2018 memo, Mr. Barr said he was writing in response to questions from the group about the use of Tinder “to meet prospective agents of the ‘Deep State’ or those with national security clearances.”

The document discussed the perils of the Espionage Act at length, and warned that Project Veritas should not try to obtain or publish any information related to national security. “In addition, as more facts and developments occur in these investigations, further legal consultation is advised,” the memo stated.

The Times previously reported that in the summer of 2018, Project Veritas had provided the money to rent a luxurious house in Georgetown, a convenient base for female operatives going on dates with federal employees at the F.B.I., State Department and Justice Department, among other agencies. In September of 2018, Project Veritas released a video as part of a series called “Deep State Unmasked.”

One of the documents mentions “Richard,” a likely reference to Richard Seddon, a former MI6 officer. Mr. Seddon was recruited to join Project Veritas in 2016 by Erik Prince, the military contractor and brother of Betsy DeVos, who served as education secretary during the Trump administration.

In 2017, Mr. Seddon trained Project Veritas operatives at Mr. Prince’s family ranch in Wyoming, according to training documents and former operatives. He helped oversee a surge in hiring, interviewing prospective employees.

Mr. Seddon, who lives in Wyoming, left Project Veritas in mid-2018 to conduct his own political spying operations in Wyoming and Colorado against Democrats and Republicans who were considered insufficiently loyal to Mr. Trump. That operation was funded at least in part by Susan Gore, a wealthy conservative and an heiress to the Gore-Tex fortune, according to people familiar with her role. (Ms. Gore has publicly denied funding the operation.)

She is the founder of a conservative organization called the Pillar of Law Institute, of which Mr. Barr, the Project Veritas lawyer, is president.

In another legal document, one about attending campaign events where the Secret Service vets attendees, the group was told its operatives could not use phony names or false pretenses.

“I believe going backstage or to closed events that require identification to the Secret Service is an invitation for a 1001 charge,” the memo said, referring to the federal law against lying to government officials, adding that in some cases, the group might be able to prevail in court using a First Amendment challenge.

The memo warned the Project Veritas employee: “I do not expect getting as close to the line as you suggest, broadly speaking, is a good opportunity for a test case.”

Mr. O’Keefe likes to describe himself as a crusading journalist exposing wrongdoing, targeting liberal groups and Democratic politicians. He has boasted on social media that he is building the “next great intelligence agency.”

Mr. O’Keefe’s operatives use fake identities and secret recordings to ensnare unsuspecting targets.

In the legal documents, Mr. Barr repeatedly refers to Project Veritas employees as “operatives” or “agents,” as well as “journalists.”

In 2017, Project Veritas began airing undercover footage of Times employees in a series called “American Pravda.” In one case, a Times editor in London was secretly recorded by two operatives who were identified by a former Project Veritas employee as James Artherton and Thor Holt. Mr. Holt did not respond to a request for comment and Mr. Artherton could not be located.

The documents show that Project Veritas had sought legal advice from a lawyer in London about conducting an undercover investigation using “covert recording of audio and video.”

The lawyer said there was “no problem” using a fake name and said the proposed operation would, “most likely, be lawful in England and Wales.”

The Times provided copies of some of the legal memos to Bill Grueskin, a professor at the Columbia Journalism School and former deputy managing editor of The Wall Street Journal and executive editor at Bloomberg News.

Mr. Grueskin, who has written about Project Veritas, said that some of Mr. Barr’s memos provided “pretty good advice,” particularly about when it is permitted to record phone conversations and other tactical recommendations.

He said that the undercover nature of Project Veritas’s work was more problematic.

“It opens you up to the charge that you’ve been intentionally deceptive and you lose your moral standing,” Mr. Grueskin said. “Every newsroom I’ve ever worked in has basically said undercover journalism was unacceptable. I’ve never had a reporter tell me he wanted to pose as somebody they were not.”

In 2010, Mr. O’ Keefe and three others pleaded guilty to a federal misdemeanor after admitting they had entered a government building in New Orleans under false pretenses as part of a sting operation.

In 2016, a Project Veritas operative infiltrated Democracy Partners, a political consulting firm, using a fake name and fabricated résumé, and made secret recordings of the staff. In his book, “American Pravda: My Fight for Truth in the Era of Fake News,” Mr. O’Keefe said the operative was “literally living out her character in America’s capital city much as Americans overseas did in Moscow during the Cold War.”

Democracy Partners later sued Project Veritas. In a ruling last month, a U.S. District Court judge said that Democracy Partners could refer to Project Veritas’s conduct as a “political spying operation” in the upcoming trial.

Michael S. Schmidt contributed reporting.