Why are some S.H.I.E.L.D. agents referred to by codenames or numbers?

Question

What is the deal with the names agents are referred to at S.H.I.E.L.D?

We have normal names

• Agent Coulson
• Agent Sitwell
• Agent May

We have code names

• Black Widow
• Hawkeye

And then we have numbered agents

• Agent 33
• Agent 13

Obviously Agent 13 and 33 aren't the 13th or the 33rd agents ever at S.H.I.E.L.D. Are these just code names used for undercover agents, and later people just keep using them? If so why is Black Widow her undercover name, and not a number?

Agent 13 tells Steve Rogers

"Captain Rogers, I'm Agent 13, S.H.I.E.L.D. Special Service" - Captain America: The Winter Soldier

You might say. "Ah Special Service, that explains it."

Except, then Agent 33's bio says:

Kara Lynn Palamas aka Agent 33 was a researcher and historian who has a special interest in classical mythology. - Marvel.wikia

She does not appear to be a member of Special Service.

Answer 1

Given the vast membership of non-technical staff, paramilitary, military, and near-superhuman operatives who work for SHIELD over the long history of the comic universe, it would appear Agents are far more often referred to by name or codename, rather than by a apparently random number. There are a few Agents who are assigned numbers but they are a very small minority.

In the Marvel Handbook (Earth-616):

• SHIELD had different operational levels and some of those levels were referred to by operation titles and Level 6 field agents were occasionally assigned numbers based on the projects they work for. Such designations are likely apocryphal now.

• This list of SHIELD Operatives which spans a good part of the organizations comic existence shows only a few numbered agents. Which suggests codenames and numbers are reserved for special types of operations.

• As for SHIELD's special operative who use codenames, super-agents are assigned names either from previous careers as spies or superheroes.

• Such operatives often head strike-teams such as SHIELD Super Agent programs or facility defense sites such as Project Pegasus.

• I suspect codenames and/or numbers are used for operatives who are on special missions who need identifying nomenclature without revealing identities on said missions.

• Given that SHIELD places counter-agents, double-agents and insurgents into enemy ranks, such numbers are likely reserved for those types of agents.

• Perhaps successful operations or operatives, once assigned a number keep that number until its retired or the operative perishes.

Production: Agents of SHIELD (TV)

In the Agents of SHIELD series, I suspect the number for Agent 33 was a play on the locker number of SHIELD Agent May which was 33 and the HYDRA agent who wore and used her May's face to infiltrate SHIELD was also "33". A coincidence? Probably not.

Answer 2

In comic continuity at least, Black Widow and Hawkeye were using those code names before they joined Shield.

Answer 3

With the exception of those agents that have earned a codename (for example Hawkeye or Black Widow), it would appear that agents are referred to by their last name unless it is taken by another agent.

I will admit up front that this answer is, at the time of writing, near pure speculation.

We have only seen two SHIELD agents referred to by numbers so far in the Marvel Cinematic Universe - Agent 33 (Kara Lynn Palamas) and Agent 13 (Sharon Carter). It is worth noting that the description in the question of Agent 33 as "a researcher and historian who has a special interest in classical mythology" is taken from the comics - we know almost nothing about Agent 33 in the Marvel Cinematic Universe.

Being as the vast majority of agents are referred to by name (Agent Coulson, Agent Simmons, Agent Sitwell etc.), it makes sense that in order to clear up any possible confusion, agents with names already in use by other agents would be assigned a number. This would make sense for Agent 13 (Sharon Carter) as the name Agent Carter is already taken by the most famous SHIELD agent of all time.

It does not seem beyond the realms of possibility that Phil Coulson was the first agent with the name "Coulson", or that Jemma Simmons was the first Agent Simmons. Likewise, I can belive that the name Agent Palamas may have been taken by a relative of Agent 33 before she joined SHIELD.

The only possible hole in this theory is that the three Koenig brothers have not been assigned numbers as far as I am aware - but being as Agents of SHIELD has constantly made references to the possibility that they may not be human (a common fan theory being that they are Life Model Decoys), this may be deliberate.

Answer 4

Because naming agents with numbers is a convenient way to annonymize them in communications and exchanges. The numbers do not have to have any specific meaning or ordering as they are just used as random code names.

Inside SHIELD I would assume you can't just be giving cool code names to everyone everytime you send them out into a cover ops mission but you want to disguise their identity as much as possible even inside reports in order to compartimentalize information.

That means you can have a mission report with a classification of "level 6" while the actual identity of Agent 23 is only known by agents of "level 8".

Numbers do have a set of desirable qualities too:

• They are sequential and do not relate to the person. No information is leaked from a number as opposed to a nick name that can be reversed engineered (i.e. it can leak information about gender)
• They are independent of nick names, so Black Widow can also be Agent 67 for all we know. Useful if you want to send Natasha on a mission but don't want the whole of S.H.I.E.L.D to know about it
• There's an unlimited number of them. If Agent 13 identity is compromised I can reasign her to Agent 89 on the next mission and her secret assignment will remain secret. If I have to give a different funny code name each time an identity is compromised I'm going to run out of wit coming up with cool names... plus it is not practical.
• Agent's won't complain about the code name. A number is a number, no emotional attachment to it (or a relatively low attachment) or opinion about it. So if I tell an agent "you're agent 13", he is not going to complain. If I tell an agent "you're now code named Butterfly" he may complain or dislike it.

In all cases a "numbered agent" is an agent that has been assigned to a cover operation and thus their real names are hidden for the duration of that mission. In the case of Agent 13 and Captain America what she's stating is: "I'm not just a random S.H.I.E.L.D agent, I'm in fact cover op agent number 13 which has been assigned for your protection under a classified level". That may or may not carry any significance to Rogers but it would carry significance to Fury or Hill which will not know her by name but will now that Agent 13 is the agent in charge of "protecting" Captain America.