I have written much about Classic Traveller skills in the past decade. However, a recent discussion on the Traveller Discord server took me back to this subject again. Not only discussing skills, but also raising the point that Travellers are competent, even regardless of formal skills. That is, a Traveller character should be able to do anything a competent interstellar adventurer would logically be able to do, even if it is not explicitly indicated on their character sheet.
This was typical to older TTRPGs. A good example of this comes from pre-2000 Dungeons & Dragons, like the Basic/Expert (B/X) and AD&D 2E I played in my youth (in the 1990s). While AD&D 2E had proficiencies, they were never construed (at least by people I played with) to be comprehensive abilities but rather interesting extra stuff the character could do. Other than explicit thief skills, we assumed a character can attempt, and often succeed at, anything logical for an adventurer to be able to do. Given surprise rules, a fighter or magic-user could definitely sneak; the thief simply gets an extra percentile roll to avoid detection even when not achieving surprise. A fighter or magic user can role-play to convince (or decieve!) NPCs to do their bidding, with risky attempts requiring a reaction roll at most. Everyone could climb reasonable walls; the theif can climb quite unreasonable ones as well! Outside of combat and spellcasting, much of the game was a relatively open conversation between the Dungeon Master and the players, always held under the assumption that characters are competent.
A starting Traveller character is at least as competent as a low-level D&D fighter: even at the formal level the Traveller can use any common weapon, drive vehicles, direct fire, perform various hospitality tasks, and use vacc suits without penalty (as per Book 1 rules - noted as "zero-level skills"). They can wear almost any armor and, with high STR and/or DEX, get much better bonuses to attack throws that a typical D&D character, even one with high ability scores! And that's just the "dry" rules - it was, and is, assumed that a Traveller can attempt anything logical for a character of their career background and characteristics to try!
Stealth? In risky situations, use the Surprise rules (Book 1). Skills can help, but are not mandatory. A military backgroudn helps. Persuation outside of specific contexts (as covered by the Admin or Streetwise skills)? Just role-play the conversaion, and if initial impressions may lead to danger, use the Reactions rules (Book 3). Again, military experience (in this case, long service) helps - and under the Book 3 rules, skills do not grant DMs for reaction!
And these are only two examples. You can solve riddles (by "player skill"), understand complex situations, recall general knowledge and education (at most, roll 2d6 under your EDU characteristic, but usually general knowledge is automatic); you can climb and jump as a competent adult; you can do a whole lot of things! Do not let your character sheet restrict you. See it as a springing board, not a comprehensive list of what your character can do.
Add skills to that. A skill is a vocation, and Skill-1 is sufficient to be employable. Skill-3 is a profession - such as a physician or proper engineer. You gain 2 skills in your initial career term, as per Book 1. You are a competent and employable character even if you are a 22-years-old freshly dischaged veteran. But skills are not everything your character is - you can do a whole lot of things by simply being a competent adult (usually) with a military background - try anything which seems logical to you and the Referee!
